mass and weight problem solving

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Mass and weight – problems and solutions

Solved problems in Newton’s laws of motion – Mass, and weight

1. The weight of a 1 kg mass at the surface of the Earth is… g = 9.8 m/s 2

Mass (m) = 1 kg

The acceleration due to gravity at the surface of the Earth (g) = 9.8 m/s 2

Wanted: weight (w)

m = mass (The SI unit of mass is the kilogram, kg)

g = acceleration due to gravity (The SI unit of g is m/s 2 )

w = weight (The SI unit of w is kg m/s 2 or Newton)

w = (1 kg)(9.8 m/s 2 ) = 9.8 kg m/s 2 = 9.8 Newton

(a) Draw the force of gravity (weight) that act on the object when the object is at rest on a table, as shown in figure (a).

(b) Draw the force of gravity (weight) and it’s components that act on an object sliding down an inclined plane , as shown in figure (b)

Mass and weight – problems and solutions 1

The direction of the weight is downward toward the center of the Earth.

w x = the horizontal component of the weight and w y = the vertical component of the weight

3. The mass of a box is 1 kg and acceleration due to gravity is 9.8 m/s 2 . Find (a) weight (b) the horizontal component and the vertical component of the weight.

Mass and weight – problems and solutions 3

Weight : w = m g = (1 kg)(9.8 m/s 2 ) = 9.8 kg m/s 2 = 9.8 Newton

The horizontal component of the weight :

w x = w sin 30 o = (9,8 N)(0,5) = 4.9 Newton

The vertical component of the weight :

w y = w cos 30 o = (9.8 N)(0.5√3) = 4.9√3 Newton

[wpdm_package id=’458′]

Mass and weight
Normal force
Newton’s second law of motion
Friction force
Motion on the horizontal surface without friction force
The motion of two bodies with the same acceleration on the rough horizontal surface with the friction force
Motion on the inclined plane without friction force
Motion on the rough inclined plane with the friction force
Motion in an elevator
The motion of bodies connected by cord and pulley
Two bodies with the same magnitude of accelerations
Rounding a flat curve – dynamics of circular motion
Rounding a banked curve – dynamics of circular motion
Uniform motion in a horizontal circle
Centripetal force in uniform circular motion

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5 Newton’s Laws of Motion

5.4 mass and weight, learning objectives.

By the end of the section, you will be able to:

Explain the difference between mass and weight
Explain why falling objects on Earth are never truly in free fall
Describe the concept of weightlessness

Mass and weight are often used interchangeably in everyday conversation. For example, our medical records often show our weight in kilograms but never in the correct units of newtons. In physics, however, there is an important distinction. Weight is the pull of Earth on an object. It depends on the distance from the center of Earth. Unlike weight, mass does not vary with location. The mass of an object is the same on Earth, in orbit, or on the surface of the Moon.

Units of Force

The equation [latex] {F}_{\text{net}}=ma [/latex] is used to define net force in terms of mass, length, and time. As explained earlier, the SI unit of force is the newton. Since [latex] {F}_{\text{net}}=ma, [/latex]

Although almost the entire world uses the newton for the unit of force, in the United States, the most familiar unit of force is the pound (lb), where 1 N = 0.225 lb. Thus, a 225-lb person weighs 1000 N.

Weight and Gravitational Force

When an object is dropped, it accelerates toward the center of Earth. Newton’s second law says that a net force on an object is responsible for its acceleration. If air resistance is negligible, the net force on a falling object is the gravitational force, commonly called its weight [latex] \overset{\to }{w} [/latex], or its force due to gravity acting on an object of mass m . Weight can be denoted as a vector because it has a direction; down is, by definition, the direction of gravity, and hence, weight is a downward force. The magnitude of weight is denoted as w . Galileo was instrumental in showing that, in the absence of air resistance, all objects fall with the same acceleration g . Using Galileo’s result and Newton’s second law, we can derive an equation for weight.

Consider an object with mass m falling toward Earth. It experiences only the downward force of gravity, which is the weight [latex] \overset{\to }{w} [/latex]. Newton’s second law says that the magnitude of the net external force on an object is [latex] {\overset{\to }{F}}_{\text{net}}=m\overset{\to }{a}. [/latex] We know that the acceleration of an object due to gravity is [latex] \overset{\to }{g}, [/latex] or [latex] \overset{\to }{a}=\overset{\to }{g} [/latex]. Substituting these into Newton’s second law gives us the following equations.

The gravitational force on a mass is its weight. We can write this in vector form, where [latex] \overset{\to }{w} [/latex] is weight and m is mass, as

In scalar form, we can write

Since [latex] g=9.80\,{\text{m/s}}^{2} [/latex] on Earth, the weight of a 1.00-kg object on Earth is 9.80 N:

When the net external force on an object is its weight, we say that it is in free fall , that is, the only force acting on the object is gravity. However, when objects on Earth fall downward, they are never truly in free fall because there is always some upward resistance force from the air acting on the object.

Acceleration due to gravity g varies slightly over the surface of Earth, so the weight of an object depends on its location and is not an intrinsic property of the object. Weight varies dramatically if we leave Earth’s surface. On the Moon, for example, acceleration due to gravity is only [latex] {1.67\,\text{m/s}}^{2} [/latex]. A 1.0-kg mass thus has a weight of 9.8 N on Earth and only about 1.7 N on the Moon.

The broadest definition of weight in this sense is that the weight of an object is the gravitational force on it from the nearest large body, such as Earth, the Moon, or the Sun. This is the most common and useful definition of weight in physics. It differs dramatically, however, from the definition of weight used by NASA and the popular media in relation to space travel and exploration. When they speak of “weightlessness” and “microgravity,” they are referring to the phenomenon we call “free fall” in physics. We use the preceding definition of weight, force [latex] \overset{\to }{w} [/latex] due to gravity acting on an object of mass m , and we make careful distinctions between free fall and actual weightlessness.

Be aware that weight and mass are different physical quantities, although they are closely related. Mass is an intrinsic property of an object: It is a quantity of matter. The quantity or amount of matter of an object is determined by the numbers of atoms and molecules of various types it contains. Because these numbers do not vary, in Newtonian physics, mass does not vary; therefore, its response to an applied force does not vary. In contrast, weight is the gravitational force acting on an object, so it does vary depending on gravity. For example, a person closer to the center of Earth, at a low elevation such as New Orleans, weighs slightly more than a person who is located in the higher elevation of Denver, even though they may have the same mass.

It is tempting to equate mass to weight, because most of our examples take place on Earth, where the weight of an object varies only a little with the location of the object. In addition, it is difficult to count and identify all of the atoms and molecules in an object, so mass is rarely determined in this manner. If we consider situations in which [latex] \overset{\to }{g} [/latex] is a constant on Earth, we see that weight [latex] \overset{\to }{w} [/latex] is directly proportional to mass m , since [latex] \overset{\to }{w}=m\overset{\to }{g}, [/latex] that is, the more massive an object is, the more it weighs. Operationally, the masses of objects are determined by comparison with the standard kilogram, as we discussed in Units and Measurement . But by comparing an object on Earth with one on the Moon, we can easily see a variation in weight but not in mass. For instance, on Earth, a 5.0-kg object weighs 49 N; on the Moon, where g is [latex] {1.67\,\text{m/s}}^{2} [/latex], the object weighs 8.4 N. However, the mass of the object is still 5.0 kg on the Moon.

Clearing a Field

A farmer is lifting some moderately heavy rocks from a field to plant crops. He lifts a stone that weighs 40.0 lb. (about 180 N). What force does he apply if the stone accelerates at a rate of [latex] 1.5\,{\text{m/s}}^{2}? [/latex]

We were given the weight of the stone, which we use in finding the net force on the stone. However, we also need to know its mass to apply Newton’s second law, so we must apply the equation for weight, [latex] w=mg [/latex], to determine the mass.

No forces act in the horizontal direction, so we can concentrate on vertical forces, as shown in the following free-body diagram. We label the acceleration to the side; technically, it is not part of the free-body diagram, but it helps to remind us that the object accelerates upward (so the net force is upward).

Figure shows a free-body diagram with vector w equal to 180 newtons pointing downwards and vector F of unknown magnitude pointing upwards. Acceleration a is equal to 1.5 meters per second squared.

[latex] \begin{array}{ccc}\hfill w& =\hfill & mg\hfill \\ \hfill m& =\hfill & \frac{w}{g}=\frac{180\,\text{N}}{9.8\,{\text{m/s}}^{2}}=18\,\text{kg}\hfill \\ \hfill \sum F& =\hfill & ma\hfill \\ \hfill F-w& =\hfill & ma\hfill \\ \hfill F-180\,\text{N}& =\hfill & (18\,\text{kg})(1.5\,{\text{m/s}}^{2})\hfill \\ \hfill F-180\,\text{N}& =\hfill & 27\,\text{N}\hfill \\ \hfill F& =\hfill & 207\,\text{N}=210\,\text{N to two significant figures}\hfill \end{array} [/latex]

Significance

To apply Newton’s second law as the primary equation in solving a problem, we sometimes have to rely on other equations, such as the one for weight or one of the kinematic equations, to complete the solution.

Check Your Understanding

For (Example) , find the acceleration when the farmer’s applied force is 230.0 N.

[latex] a=2.78\,{\text{m/s}}^{2} [/latex]

Can you avoid the boulder field and land safely just before your fuel runs out, as Neil Armstrong did in 1969? This version of the classic video game accurately simulates the real motion of the lunar lander, with the correct mass, thrust, fuel consumption rate, and lunar gravity. The real lunar lander is hard to control.

Use this interactive simulation to move the Sun, Earth, Moon, and space station to see the effects on their gravitational forces and orbital paths. Visualize the sizes and distances between different heavenly bodies, and turn off gravity to see what would happen without it.

Mass is the quantity of matter in a substance.
The weight of an object is the net force on a falling object, or its gravitational force. The object experiences acceleration due to gravity.
Some upward resistance force from the air acts on all falling objects on Earth, so they can never truly be in free fall.
Careful distinctions must be made between free fall and weightlessness using the definition of weight as force due to gravity acting on an object of a certain mass.

Conceptual Questions

What is the relationship between weight and mass? Which is an intrinsic, unchanging property of a body?

How much does a 70-kg astronaut weight in space, far from any celestial body? What is her mass at this location?

The astronaut is truly weightless in the location described, because there is no large body (planet or star) nearby to exert a gravitational force. Her mass is 70 kg regardless of where she is located.

Which of the following statements is accurate?

(a) Mass and weight are the same thing expressed in different units.

(b) If an object has no weight, it must have no mass.

(d) Mass and inertia are different concepts.

(e) Weight is always proportional to mass.

When you stand on Earth, your feet push against it with a force equal to your weight. Why doesn’t Earth accelerate away from you?

The force you exert (a contact force equal in magnitude to your weight) is small. Earth is extremely massive by comparison. Thus, the acceleration of Earth would be incredibly small. To see this, use Newton’s second law to calculate the acceleration you would cause if your weight is 600.0 N and the mass of Earth is [latex] 6.00\,×\,{10}^{24}\,\text{kg} [/latex].

How would you give the value of [latex] \overset{\to }{g} [/latex] in vector form?

The weight of an astronaut plus his space suit on the Moon is only 250 N. (a) How much does the suited astronaut weigh on Earth? (b) What is the mass on the Moon? On Earth?

a. [latex] \begin{array}{ccc}\hfill {w}_{\text{Moon}}& =\hfill & m{g}_{\text{Moon}}\hfill \\ \hfill m& =\hfill & 150\,\text{kg}\hfill \\ \hfill {w}_{\text{Earth}}& =\hfill & 1.5\,×\,{10}^{3}\,\text{N}\hfill \end{array} [/latex]; b. Mass does not change, so the suited astronaut’s mass on both Earth and the Moon is [latex] 150\,\text{kg.} [/latex]

Suppose the mass of a fully loaded module in which astronauts take off from the Moon is [latex] 1.00\,×\,{10}^{4} [/latex] kg. The thrust of its engines is [latex] 3.00\,×\,{10}^{4} [/latex] N. (a) Calculate the module’s magnitude of acceleration in a vertical takeoff from the Moon. (b) Could it lift off from Earth? If not, why not? If it could, calculate the magnitude of its acceleration.

A rocket sled accelerates at a rate of [latex] {49.0\,\text{m/s}}^{2} [/latex]. Its passenger has a mass of 75.0 kg. (a) Calculate the horizontal component of the force the seat exerts against his body. Compare this with his weight using a ratio. (b) Calculate the direction and magnitude of the total force the seat exerts against his body.

a. [latex] \begin{array}{ccc}\hfill {F}_{\text{h}}& =\hfill & 3.68\,×\,{10}^{3}\,\text{N and}\hfill \\ \hfill w& =\hfill & 7.35\,×\,{10}^{2}\,\text{N}\hfill \\ \hfill \frac{{F}_{\text{h}}}{w}& =\hfill & 5.00\,\text{times greater than weight}\hfill \end{array} [/latex];

b. [latex] \begin{array}{ccc}\hfill {F}_{\text{net}}& =\hfill & 3750\,\text{N}\hfill \\ \hfill \theta & =\hfill & 11.3\text{°}\,\text{from horizontal}\hfill \end{array} [/latex]

Repeat the previous problem for a situation in which the rocket sled decelerates at a rate of [latex] {201\,\text{m/s}}^{2} [/latex]. In this problem, the forces are exerted by the seat and the seat belt.

A body of mass 2.00 kg is pushed straight upward by a 25.0 N vertical force. What is its acceleration?

[latex] \begin{array}{ccc}\hfill w& =\hfill & 19.6\,\text{N}\hfill \\ \hfill {F}_{\text{net}}& =\hfill & 5.40\,\text{N}\hfill \\ \hfill {F}_{\text{net}}& =\hfill & ma⇒a=2.70\,{\text{m/s}}^{2}\hfill \end{array} [/latex]

A car weighing 12,500 N starts from rest and accelerates to 83.0 km/h in 5.00 s. The friction force is 1350 N. Find the applied force produced by the engine.

A body with a mass of 10.0 kg is assumed to be in Earth’s gravitational field with [latex] g=9.80\,{\text{m/s}}^{2} [/latex]. What is its acceleration?

[latex] 0.60\hat{i}-8.4\hat{j}\,{\text{m/s}}^{2} [/latex]

A fireman has mass m ; he hears the fire alarm and slides down the pole with acceleration a (which is less than g in magnitude). (a) Write an equation giving the vertical force he must apply to the pole. (b) If his mass is 90.0 kg and he accelerates at [latex] 5.00\,{\text{m/s}}^{2}, [/latex] what is the magnitude of his applied force?

A baseball catcher is performing a stunt for a television commercial. He will catch a baseball (mass 145 g) dropped from a height of 60.0 m above his glove. His glove stops the ball in 0.0100 s. What is the force exerted by his glove on the ball?

When the Moon is directly overhead at sunset, the force by Earth on the Moon, [latex] {F}_{\text{EM}} [/latex], is essentially at [latex] 90\text{°} [/latex] to the force by the Sun on the Moon, [latex] {F}_{\text{SM}} [/latex], as shown below. Given that [latex] {F}_{\text{EM}}=1.98\,×\,{10}^{20}\,\text{N} [/latex] and [latex] {F}_{\text{SM}}=4.36\,×\,{10}^{20}\,\text{N}, [/latex] all other forces on the Moon are negligible, and the mass of the Moon is [latex] 7.35\,×\,{10}^{22}\,\text{kg}, [/latex] determine the magnitude of the Moon’s acceleration.

Figure shows a circle labeled moon. An arrow from it, pointing up is labeled F subscript EM. Another arrow from it pointing right is labeled F subscript SM.

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5.4 Mass and Weight

Learning objectives.

By the end of this section, you will be able to:

Explain the difference between mass and weight
Explain why objects falling through the air are never truly in free fall
Describe the concept of weightlessness

Units of Force

The equation F net = m a F net = m a is used to define net force in terms of mass, length, and time. As explained earlier, the SI unit of force is the newton. Since F net = m a , F net = m a ,

Weight and Gravitational Force

When an object is dropped, it accelerates toward the center of Earth. Newton’s second law says that a net force on an object is responsible for its acceleration. If air resistance is negligible, the net force on a falling object is the gravitational force, commonly called its weight w → w → , or its force due to gravity acting on an object of mass m . Weight can be denoted as a vector because it has a direction; down is, by definition, the direction of gravity, and hence, weight is a downward force. The magnitude of weight is denoted as w . Galileo was instrumental in showing that, in the absence of air resistance, all objects fall with the same acceleration g . Using Galileo’s result and Newton’s second law, we can derive an equation for weight.

Consider an object with mass m falling toward Earth. It experiences only the downward force of gravity, which is the weight w → w → . Newton’s second law says that the magnitude of the net external force on an object is F → net = m a → . F → net = m a → . We know that the acceleration of an object due to gravity is g → , g → , or a → = g → a → = g → . Substituting these into Newton’s second law gives us the following equations.

The gravitational force on a mass is its weight. We can write this in vector form, where w → w → is weight and m is mass, as

In scalar form, we can write

Since g = 9.80 m/s 2 g = 9.80 m/s 2 on Earth, the weight of a 1.00-kg object on Earth is 9.80 N:

When the net external force on an object is its weight, we say that it is in free fall , that is, the only force acting on the object is gravity. However, when objects on Earth fall downward through the air, they are never truly in free fall because there is always some upward resistance force from the air acting on the object.

Acceleration due to gravity g varies slightly over the surface of Earth, so the weight of an object depends on its location and is not an intrinsic property of the object. Weight varies dramatically if we leave Earth’s surface. On the Moon, for example, acceleration due to gravity is only 1.62 m/s 2 1.62 m/s 2 . A 1.0-kg mass thus has a weight of 9.8 N on Earth and only about 1.6 N on the Moon.

The broadest definition of weight in this sense is that the weight of an object is the gravitational force on it from the nearest large body, such as Earth, the Moon, or the Sun. This is the most common and useful definition of weight in physics. It differs dramatically, however, from the definition of weight used by NASA and the popular media in relation to space travel and exploration. When they speak of “weightlessness” and “microgravity,” they are referring to the phenomenon we call “free fall” in physics. We use the preceding definition of weight, force w → w → due to gravity acting on an object of mass m , and we make careful distinctions between free fall and actual weightlessness.

It is tempting to equate mass to weight, because most of our examples take place on Earth, where the weight of an object varies only a little with the location of the object. In addition, it is difficult to count and identify all of the atoms and molecules in an object, so mass is rarely determined in this manner. If we consider situations in which g → g → is a constant on Earth, we see that weight w → w → is directly proportional to mass m , since w → = m g → , w → = m g → , that is, the more massive an object is, the more it weighs. Operationally, the masses of objects are determined by comparison with the standard kilogram, as we discussed in Units and Measurement . But by comparing an object on Earth with one on the Moon, we can easily see a variation in weight but not in mass. For instance, on Earth, a 5.0-kg object weighs 49 N; on the Moon, where g is 1.67 m/s 2 1.67 m/s 2 , the object weighs 8.4 N. However, the mass of the object is still 5.0 kg on the Moon.

Example 5.8

Clearing a field, significance, check your understanding 5.6.

For Example 5.8 , find the acceleration when the farmer’s applied force is 230.0 N.

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StickMan Physics

Animated Physics Lessons

Mass and Weight

Learn the difference between mass (m) and weight (F w ). Find out how to convert to mass from weight and from weight to mass.

Watch the video as we go through the content and problems set or go through the same material below

Learning Targets

I know the difference between mass and weight
I can calculate mass from weight and weight from mass using F w = mg
I can draw a Force Diagram of an object on a horizontal surface of any planet

Mass is a measurement of matter (molecular composition) of an object. Since an objects molecular composition remains when location changes, mass never changes.

Weight is a measure of the force of gravity on an objects mass. This is directly related to mass but will change with location as the force and acceleration due to gravity changes.

Weight equals mass times gravity

On the Earth's surface, the accepted value for acceleration due to gravity (g) is 9.81 m/s 2
In some lessons we had you use a less specific rounded number of 10 m/s 2

Weight Changes When (g) Changes

On Earth, your weight is caused by the earths pull on you. In a future lesson we will see that weight is the result of the your mass, the earths mass, and the distance between you and Earth.

We will solve problems on this page using an average surface acceleration due to gravity

More massive interstellar objects have a higher surface acceleration due to gravity ( g ).
The higher the acceleration due to gravity ( g ) the higher the weight ( F w )

Mass, Radius, and Acceleration due to Gravity of Planets

Mass, Radius, and Acceleration due to Gravity of Other Interstellar Objects

Example questions (mass and weight).

1. What is 76 kg Natalia's weight on earth where the acceleration due to gravity is 9.81 m/s 2 ?

See Solution

F w = (76)(9.81)= 745.56 N

2. What is Natalia's weight on the moon where the acceleration due to gravity is 1.62 m/s 2 ?

F w = (76)(1.62)= 123.12 N

3. If 76 kg Natalia went to Neptune where the surface acceleration due to gravity is 11.15 m/s 2 , would her mass or weight change and what would each be?

Mass would still be 76 kg wither location and weight would change

F w = (76)(11.15) = 847.4 N

Normal Force Equals Weight on a Horizontal Surface

Notice in the force diagrams :

Mass ( m ) of 10 kg does not change
Weight ( F w ) changes with the acceleration due to gravity
The normal ( F N )force changes with weight ( F w )

Normal force is the force created by weight on a surface pushing back upwards perpendicular to the surface. Perpendicular to any horizontal surface will be up.

Normal force equals weight on a horizontal surface

Problem Set

1. What is the weight of a 25 kg object on Pluto where the acceleration due to gravity is 0.62 m/s 2 ?

F w = 15.5 N

2. Draw a force diagram including the normal force of this 25 kg object on a horizontal surface of Pluto where the acceleration due to gravity is 0.62 m/s 2 ?

3. What is the mass of a 25 kg object on Pluto where the acceleration due to gravity is 0.62 m/s 2 ?

m = 25 kg (does not change)

4. What is the weight of a 25 kg object on Mars where the acceleration due to gravity is 3.72 m/s 2 ?

5. What is the mass of a 100 N object on the Moon where the acceleration due to gravity is 1.62 m/s 2 ?

6. Draw a force diagram including the normal force of a 100 N object on the surface of the Moon where the acceleration due to gravity is 1.62 m/s 2 ?

7. If you weigh 1177.2 N on Earth where the acceleration due to gravity is 9.81 m/s 2 what is your mass on Uranus where the acceleration due to gravity is 8.69 m/s 2 ?

8. If you weigh 1177.2 N on Earth where the acceleration due to gravity is 9.81 m/s 2 what is your weight on Uranus where the acceleration due to gravity is 8.69 m/s 2 ?

F w = 1042.8 N

Mass and Weight Quiz

Joe has a mass of 54 kg. What is his mass on the moon where the acceleration due to gravity is 1.62 m/s 2 ?

Mass does not change. Weight does depending on the acceleration due to gravity.

Joe has a mass of 54 kg. What is his weight on the moon where the acceleration due to gravity is 1.62 m/s 2 ?

g = 1.62 m/s 2

F w = (54)(1.62) = 87.48 N

Joe has a mass of 54 kg. What is his weight on the earth?

g = 9.8 m/s 2

F w = (54)(9.8) = 529.2 N

Which changes depending on your location?

Mass (kg) never changes because it is a measure of the matter that you are composed of. You are the same matter on earth or on the moon.

Weight (F w ) changes when g changes. g changes depending on your altitude on earth, in space, or on another planet (it is not always 9.8 m/s 2 which is why many classes use a more rounded 10 m/s 2 instead.

Which is the term for the molecules that make up an object.

Matter is composed of the atoms/molecules that make up an object

What would happen to your weight if you were on a planet with twice the acceleration due to gravity?

Your score is

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6.12: Mass and Weight

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Learning Objectives

Explain the difference between mass and weight
Explain why falling objects on Earth are never truly in free fall
Describe the concept of weightlessness

Units of Force

The equation F net = ma is used to define net force in terms of mass, length, and time. As explained earlier, the SI unit of force is the newton. Since F net = ma,

\[1\; N = 1\; kg \cdotp m/s^{2} \ldotp \nonumber\]

Weight and Gravitational Force

When an object is dropped, it accelerates toward the center of Earth. Newton’s second law says that a net force on an object is responsible for its acceleration. If air resistance is negligible, the net force on a falling object is the gravitational force, commonly called its weight $\vec{w}$, or its force due to gravity acting on an object of mass m. Weight can be denoted as a vector because it has a direction; down is, by definition, the direction of gravity, and hence, weight is a downward force. The magnitude of weight is denoted as w. Galileo was instrumental in showing that, in the absence of air resistance, all objects fall with the same acceleration g. Using Galileo’s result and Newton’s second law, we can derive an equation for weight.

Consider an object with mass m falling toward Earth. It experiences only the downward force of gravity, which is the weight $\vec{w}$. Newton’s second law says that the magnitude of the net external force on an object is $\vec{F}_{net} = m \vec{a}$. We know that the acceleration of an object due to gravity is $\vec{g}$, or $\vec{a} = \vec{g}$. Substituting these into Newton’s second law gives us the following equations.

Defintion: Weight

The gravitational force on a mass is its weight. We can write this in vector form, where $\vec{w}$ is weight and m is mass, as

\[\vec{w} = m \vec{g} \ldotp \label{5.8}\]

In scalar form, we can write

\[w = mg \ldotp \label{5.9}\]

Since g = 9.80 m/s 2 on Earth, the weight of a 1.00-kg object on Earth is 9.80 N:

\[w = mg = (1.00\; kg)(9.80 m/s^{2}) = 9.80\; N \ldotp\]

Acceleration due to gravity g varies slightly over the surface of Earth, so the weight of an object depends on its location and is not an intrinsic property of the object. Weight varies dramatically if we leave Earth’s surface. On the Moon, for example, acceleration due to gravity is only 1.67 m/s 2 . A 1.0-kg mass thus has a weight of 9.8 N on Earth and only about 1.7 N on the Moon.

The broadest definition of weight in this sense is that the weight of an object is the gravitational force on it from the nearest large body, such as Earth, the Moon, or the Sun. This is the most common and useful definition of weight in physics. It differs dramatically, however, from the definition of weight used by NASA and the popular media in relation to space travel and exploration. When they speak of “weightlessness” and “microgravity,” they are referring to the phenomenon we call “free fall” in physics. We use the preceding definition of weight, force $\vec{w}$ due to gravity acting on an object of mass m, and we make careful distinctions between free fall and actual weightlessness.

It is tempting to equate mass to weight, because most of our examples take place on Earth, where the weight of an object varies only a little with the location of the object. In addition, it is difficult to count and identify all of the atoms and molecules in an object, so mass is rarely determined in this manner. If we consider situations in which $\vec{g}$ is a constant on Earth, we see that weight $\vec{w}$ is directly proportional to mass m, since $\vec{w} = m \vec{g}$, that is, the more massive an object is, the more it weighs. Operationally, the masses of objects are determined by comparison with the standard kilogram, as we discussed in Units and Measurement . But by comparing an object on Earth with one on the Moon, we can easily see a variation in weight but not in mass. For instance, on Earth, a 5.0-kg object weighs 49 N; on the Moon, where g is 1.67 m/s 2 , the object weighs 8.4 N. However, the mass of the object is still 5.0 kg on the Moon.

Example $\PageIndex{1}$: Clearing a Field

\[w = mg \nonumber \]

\[m = \frac{w}{g} = \frac{180\; N}{9.8\; m/s^{2}} = 18\; kg \nonumber\]

\[\sum F = ma \nonumber\]

\[F - w = ma \nonumber\]

\[F - 180\; N = (18\; kg)(1.5\; m/s^{2}) \nonumber\]

\[F - 180\; N = 27\; N \nonumber\]

\[F = 207\; N = 210\; N\; \text{ to two significant figures} \nonumber\]

Significance

Exercise $\PageIndex{1}$

For $\PageIndex{1}$, find the acceleration when the farmer’s applied force is 230.0 N

practice problem 1

Use the weight formula.

W = mg

Solve for mass. Substitute one newton for weight and one standard earth gravity for gravity.

The 96.7 gram tangerine comes closest to this value. Not all tangerines weigh 98.7 grams, however, so this is only a rule of thumb. There are certainly apples, bananas, oranges, tomatoes, and other fruits out there with a mass of approximately 102 grams and thus a weight of approximately one newton.

Those of you familiar with multiple choice tests should have eliminated the chicken egg as a possible answer. A chicken egg is only metaphorically the "fruit of the chicken".

practice problem 2

Here's the way I usually do it — using values I've memorized from years of use.

Here's a more accurate way to do it — using values that are exact by definition.

Not quite a quarter pound, but you get the idea.

The fraction 9 40 gives a decimal expansion of 0.225, which is accurate to three significant figures. Not my favorite fraction, but it gets the job done. With sixteen avoirdupois ounces in a pound, one newton is also about 3½ ounces.

practice problem 3

Practice problem 4.

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Education and Communications
Classical Mechanics

How Find the Weight of an Object Using Mass and Gravity

Last Updated: March 19, 2024 Fact Checked

This article was co-authored by Sean Alexander, MS and by wikiHow staff writer, Johnathan Fuentes . Sean Alexander is an Academic Tutor specializing in teaching mathematics and physics. Sean is the Owner of Alexander Tutoring, an academic tutoring business that provides personalized studying sessions focused on mathematics and physics. With over 15 years of experience, Sean has worked as a physics and math instructor and tutor for Stanford University, San Francisco State University, and Stanbridge Academy. He holds a BS in Physics from the University of California, Santa Barbara and an MS in Theoretical Physics from San Francisco State University. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 1,352,106 times.

If you’re taking a physics class, you’ll probably be asked to calculate weight from mass. But how do you do this, exactly? We’ve got you covered. While it sounds tricky, calculating weight from mass is very straightforward if you know which formula to use. This article will teach you that formula, plus how to use it when you encounter physics problems in class. As a bonus, we’ve included some practice problems to help these concepts sink in. Keep reading to learn how to calculate weight from mass on your next physics quiz, test, or homework assignment.

Things You Should Know

The weight of an object equals the force of gravity exerted on that object. The mass of an object is always the same, but its weight changes depending on gravity.

$w=m*g$

Weight from Mass Calculation Help

Calculating Weight

If you're using meters , the gravitational acceleration at the Earth's surface is 9.8 m/s 2 . Always use m/s 2 for acceleration, unless you’re instructed to do otherwise.
If you're asked to use feet , instead of meters , the gravitational acceleration on Earth is 32.2 ft/s 2 . This is the same unit, it's just converted from meters to feet . Luckily, you’re very unlikely to encounter a problem with acceleration written in ft/s 2 .

The gravitational acceleration on the moon is different from the gravitational acceleration on the Earth. Acceleration due to gravity on the moon is about 1.622 m/s 2 , or about 1/6 of the acceleration that it is here on Earth. That's why you weigh 1/6 of your Earth-weight on the moon. [4] X Research source
The gravitational acceleration on the sun is different from the gravitational acceleration on the Earth and moon. Acceleration due to gravity on the sun is about 274.0 m/s 2 , or about 28 times the acceleration that it is here on Earth. That's why you would weigh 28 times your Earth-weight on the sun (if you could survive!). [5] X Research source

$Step 4 Plug the numbers into the equation F = m g {\displaystyle F=mg} .$

Sample Problems

Catching Mistakes

You only have weight while you're " wait "ing on Earth, but even " mass "tronauts have mass.

Step 2 Always use scientific units: kg, N, and m/s2.

1 pound-force = ~4.448 newtons
1 foot = ~0.3048 meters

Community Q&A

Addendum: Weights Expressed in kgf

A Newton is a SI-unit. Quite often the weight is expressed in kilogramforce or kgf. This is not a SI-unit, therefore less impeccable. But it is very convenient for comparing weights anywhere with weights on Earth.
1 kgf = 9.8166 N.
Divide the calculated number of Newtons by 9.80665, or use the last column when available.
The weight of the 101 kg astronaut is 101.3 kgf on the North Pole, and 16.5 kgf on the moon.
What is an SI-unit? It stands for Systeme International d'Unites, a complete metric system of units of measurement for scientists.
The most difficult part is understanding the difference between weight and mass as people tend to use the words 'weight' and 'mass' interchangeably. They use kilograms for weight, when they should use Newton, or at least kilogramforce. Even your doctor may discuss your weight, when he meant to discuss your mass. Thanks Helpful 0 Not Helpful 0
The gravitational acceleration g can also be expressed in N/kg. 1 N/kg = 1 m/s 2 exactly. So the numbers remain the same. Thanks Helpful 0 Not Helpful 0
An astronaut with a mass of 100 kg will weigh 983.2 N on the North Pole, and 162.0 N on the moon. On a neutron star, he'll weigh even more, but he probably won't notice. Thanks Helpful 0 Not Helpful 0

↑ https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wteq.html
↑ https://web.mst.edu/~reflori/be150/Dyn%20Lecture%20Videos/F=ma%20Particle%20Straight%20Line%201/F=ma%20Particle%20Straight%20Line%201.pdf
↑ https://www.physicsclassroom.com/class/1DKin/Lesson-5/Acceleration-of-Gravity
↑ https://hypertextbook.com/facts/2004/MichaelRobbins.shtml
↑ https://www.smartconversion.com/otherInfo/gravity_of_planets_and_the_sun.aspx

About This Article

To find weight when you already know the mass, use the formula weight = mass times gravitational acceleration. Remember that on the surface of the earth, gravitational acceleration is always 9.8 m/s^2, so simply plug in the mass and multiply it by 9.8 to get the weight in newtons. For sample problems and tips for checking your answer and catching mistakes, read on! Did this summary help you? Yes No

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Newton’s Laws of Motion

Mass and Weight

Learning objectives.

By the end of the section, you will be able to:

Explain the difference between mass and weight
Explain why falling objects on Earth are never truly in free fall
Describe the concept of weightlessness

Units of Force

${F}_{\text{net}}=ma$

Weight and Gravitational Force

$\stackrel{\to }{w}$

In scalar form, we can write

${1.67\phantom{\rule{0.2em}{0ex}}\text{m/s}}^{2}$

$\stackrel{\to }{g}$

Solution No forces act in the horizontal direction, so we can concentrate on vertical forces, as shown in the following free-body diagram. We label the acceleration to the side; technically, it is not part of the free-body diagram, but it helps to remind us that the object accelerates upward (so the net force is upward).

Significance To apply Newton’s second law as the primary equation in solving a problem, we sometimes have to rely on other equations, such as the one for weight or one of the kinematic equations, to complete the solution.

Check Your Understanding For (Figure) , find the acceleration when the farmer’s applied force is 230.0 N.

$a=2.78\phantom{\rule{0.2em}{0ex}}{\text{m/s}}^{2}$

Mass is the quantity of matter in a substance.
The weight of an object is the net force on a falling object, or its gravitational force. The object experiences acceleration due to gravity.
Some upward resistance force from the air acts on all falling objects on Earth, so they can never truly be in free fall.
Careful distinctions must be made between free fall and weightlessness using the definition of weight as force due to gravity acting on an object of a certain mass.

Conceptual Questions

What is the relationship between weight and mass? Which is an intrinsic, unchanging property of a body?

How much does a 70-kg astronaut weight in space, far from any celestial body? What is her mass at this location?

Which of the following statements is accurate?

(a) Mass and weight are the same thing expressed in different units.

(b) If an object has no weight, it must have no mass.

(d) Mass and inertia are different concepts.

(e) Weight is always proportional to mass.

When you stand on Earth, your feet push against it with a force equal to your weight. Why doesn’t Earth accelerate away from you?

$6.00\phantom{\rule{0.2em}{0ex}}×\phantom{\rule{0.2em}{0ex}}{10}^{24}\phantom{\rule{0.2em}{0ex}}\text{kg}$

The weight of an astronaut plus his space suit on the Moon is only 250 N. (a) How much does the suited astronaut weigh on Earth? (b) What is the mass on the Moon? On Earth?

$\begin{array}{ccc}\hfill {w}_{\text{Moon}}& =\hfill & m{g}_{\text{Moon}}\hfill \\ \hfill m& =\hfill & 150\phantom{\rule{0.2em}{0ex}}\text{kg}\hfill \\ \hfill {w}_{\text{Earth}}& =\hfill & 1.5\phantom{\rule{0.2em}{0ex}}×\phantom{\rule{0.2em}{0ex}}{10}^{3}\phantom{\rule{0.2em}{0ex}}\text{N}\hfill \end{array}$

A body of mass 2.00 kg is pushed straight upward by a 25.0 N vertical force. What is its acceleration?

$\begin{array}{ccc}\hfill w& =\hfill & 19.6\phantom{\rule{0.2em}{0ex}}\text{N}\hfill \\ \hfill {F}_{\text{net}}& =\hfill & 5.40\phantom{\rule{0.2em}{0ex}}\text{N}\hfill \\ \hfill {F}_{\text{net}}& =\hfill & ma⇒a=2.70\phantom{\rule{0.2em}{0ex}}{\text{m/s}}^{2}\hfill \end{array}$

A car weighing 12,500 N starts from rest and accelerates to 83.0 km/h in 5.00 s. The friction force is 1350 N. Find the applied force produced by the engine.

$0.60\stackrel{^}{i}-8.4\stackrel{^}{j}\phantom{\rule{0.2em}{0ex}}{\text{m/s}}^{2}$

${F}_{\text{EM}}$

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Resources tagged with: Mass and weight

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WORD PROBLEMS INVOLVING MASS AND WEIGHT

The mass of an object is the amount of matter it contains.

Example 1 :

If one egg has a mass of 55 g, find the total mass of eggs in 50 cartons, each containing 12 eggs.

Mass of 1 egg = 55 g

Number of eggs in each carton = 12

Total number of cartons = 50

Total mass = 55 x 12 x 50

= 33000 g

1000g = 1 kg

= 33 kg

Example 2 :

Find the total mass of 32 chocolates, each of mass 28 grams.

Number of chocolates = 32

Mass of each chocolate = 28 grams

Total mass = 32 x 28

= 896 grams

Example 3 :

If a clothes peg has a mass of 6.5 g, how many pegs are there in a 13 kg box?

Mass of 1 cloth peg = 6.5 g

Mass of box = 13 kg

1000 grams = 1 kg

Converting kg to grams, we get

= 13000 grams

Number of pegs = 13000/6.5

= 2000 pegs

Example 4 :

If a roof tile has mass 1.25 kilograms, how many tiles could a van with a load limit of 8 tonnes carry?

1000 kg = 1 tonne

8 tonnes = 8(1000)

= 8000 kg

Mass of 1 roof tile = 1.25 kg

Number of roof tiles carried by the van = 8000/1.25

= 6400 tiles

Example 5 :

Find the total mass in tonnes of 3500 books, each with mass 800 grams.

Mass of each book = 800 grams

Total number of books = 3500

Mass of 3500 books = 800 x 3500

= 2800000 grams

= 2800000/1000

= 2800 kg

1000 kg = 1 tonne

= 2800/1000

= 2.8 tonnes

Example 6 :

If the mass of 8000 oranges is 1.04 tonnes, what is the average mass of one orange?

Total number of oranges = 8000

Weight of oranges = 1.04 tonnes

= 1.04 (1000)

= 1040 kg

= 1040(1000)

= 1040000 grams

Average weight of 1 orange = 1040000 / 8000

= 130 grams

So, mass of 1 orange is 130 grams.

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This unit comprises six problems for students to apply and interpret measurement of mass. Students are also introduced to the concepts of net and gross mass.

Select the appropriate standard unit of measurement for a specific application.
Measure masses with appropriate measuring devices.
Measure net and gross mass.

Mass is the force created by gravity acting of on an object. Mass is felt as weight, a force that pulls the object towards the centre of the Earth. Mass is measured in units based on grams, and tonnes. Larger or smaller units are created by combining or equally partitioning these units. One kilogram is a combination of 1000 grams (kilo means 1000). One milligram is 1/1000 of a gram and one microgram is 1/ 1 000 000 of a gram. The units for mass come from the mass of water. One cubic metre of water has a mass of 1 tonne, or 1000 kilograms. One millilitre of water has a mass of one gram.

Note that in the New Zealand Curriculum document, “weight” and “mass” are used interchangeably. In a science context, the definition of “force created by gravity acting on an object” would often be equated with weight, not mass. Consider the scientific knowledge of your students (e.g. are they studying forces in science). It may be more appropriate to define mass as the amount of matter in an object (measured in kilograms) and weight using the adorementioned definition (measured in Newtons, N).

The learning opportunities in this unit can be differentiated by providing or removing support to students and by varying the task requirements. Ways to support students include:

letting students attempt problems using physical materials as much as possible, so they develop a ‘feel’ for the benchmark units
directly modelling measurement with tools, like digital scales for mass
providing opportunities for students to copy the correct use of tools
clarifying the language of measurement units, such as “kilogram” as a mass that is made up of 1000 grams
clarifying the meaning of symbols, e.g. 45g as 45 grams, and 45kg as 45 kilograms; 45t as 45 tonnes
encouraging students to work collaboratively (mahi tahi) to share and justify their ideas
easing the calculation demands by providing calculators where appropriate.

Tasks can be varied in many ways including:

reducing the complexity of the numbers involved in the station tasks, e.g. whole number versus fraction dimensions. The choice of measurement units influences the difficulty of calculation as well as the level of precision
allowing physical solutions with manipulatives before requiring abstract (in the head) anticipation of measures
creating or using models of standard units, e.g. 1 litre of water for the mass of 1 kilogram
reducing the demands for a product, e.g. less calculations and words, and more diagrams and models.

The context for this unit can be adapted to suit the interests and cultural backgrounds of your students. Use the interests of your students to create contexts that will engage them. Students may be interested in the mass of rugby players. Students from large whānau, or who prepare food for large numbers of people, may relate to measuring quantities to scale up recipes. Carrying heavy objects was a major problem for pre-European Māori. How did they carry heavy loads, or move waka? Counting on Frank by Rod Clement may inspire some students to look for eccentric ways to apply measurement to their daily lives. For example, the human body is 60% water, by mass. How much water is in their body?

Te reo Māori vocabulary terms such as maihea (weight / mass), karamu (gram), manokaramu (kilogram), and tana (tonne) could be introduced in this unit and used throughout other mathematical learning.

Station 1: Copymaster 1 , $1, $2 and 50c coins, scales (preferably digital and able to weigh in grams), metre ruler
Station 2: Copymaster 2 , calculator
Station 3: Copymaster 3 , calculator
Station 4: Copymaster 4 , access to the internet.
Station 5: Copymaster 5 , 1L measuring jug, five different sized plastic containers, scales, eyedropper
Station 6: Copymaster 6 , can of dog food, supermarket bags, calculator

The following six stations provide a range of problems for students to apply and interpret measurement of mass. Consider what would be the most effective method for introducing these to your class. You could work on them as a whole class and provide support to groups of students. Alternatively, you could use another relevant igniting activity to introduce the context for learning, before directing students to work on one or more of these stations independently, or in small groups. These stations could serve as the basis for learning in different sessions, or could be used as one session. At the conclusion of these stations, students draw on the problems presented and create their own stations to be used in other lessons.

Station 1: A kilo of coins

You have won a prize which can be just one of the following:

1 kilogram of $1 coins
A 1.5 metre long trail of $2 coins (lying flat and touching)
A 0.5 metre high stack of 50c coins

What is your choice?

1 kg of $1 coins (1000 ÷ 8 = 125 coins, so $125)

1.5 metre of $2 coins (1500 ÷ 26.5 = 57 coins, so $114)

0.5 metre stack of 50c coins (500 ÷ 1.7 = 294 coins, so $147)

Station 2: Largest Lasagne

This problem could be adapted to reflect food that is meaningful to your students (e.g. the largest tray of pani popo).

The world’s largest lasagne was made in 2012 at a restaurant in Wieliczka, Poland. It weighed 4865 kg and measured 25 m x 2.5 m.

The ingredients were:

2500kg of pasta, 800kg of mince, 400kg of mozzarella cheese, 100kg of peas, 100kg of carrots, and equal amounts of white sauce and tomato sauce.

How much did the white sauce and tomato sauce weigh?
What would be the size of a 500g piece from the lasagne?
How many people could be fed with the whole lasagne? Show how you arrived at your estimate.
The other ingredients total 3900kg so the sauces must weigh 4865 – 3900 = 965 kg. 500L of each sauce was used. Does that sound right?
A 500g piece would be about 1/10 000 of the whole lasagne. One way is to cut both the length and width into 100 parts, since 100 x 100 = 10 000. A single piece would measure 25cm x 2.5cm. That’s a bit skinny so 12.5cm x 5cm might work better.
The lasagne was actually cut into 10 000 pieces so that’s how many people were fed. Each piece had a mass of 0.486 kg or 486 grams. That is a good serving of lasagne.

Station 3: Weighing Tonnes

Konsihiki was the largest active sumo wrestler in the world with a mass of 287 kg. Now he is retired.

How many Konishikis weigh as much as 1 tonne?

Make a table of tonne weights using objects in the classroom. Remember that 1000 kg is a tonne.

The number of Konshihikis in 1 tonne equals 3.48, about 3 and ½ of him.

To find how many of any object make 1 tonne, divided 1 000 by the weight of the object in kilograms. For example, if a schoolbag weighs 5kg then 1 000 ÷ 5 = 200 make 1 tonne.

Station 4: Jumbo facts

Find out facts about the mass of very large animals and make a report about these animals for the class. To get you started here are some facts about the Blue Whale, which can be seen in New Zealand waters.

The blue whale is the largest animal living on Earth. It can reach up to nearly 30 metres in length and weigh up to 180 tonnes (t). Their tongues alone can weigh as much as some elephants and their hearts are huge, weighing a whopping 180kg. They have the largest babies on Earth. When they are first born they can be 8 metres (m) in length and weigh 4000kg. Imagine a jet engine that registers at 140 decibels. A blue whale, when it calls, registers at 188 decibels. Compare the facts about the Blue Whale with the large African elephant

The African elephant is the biggest animal on land. Fully grown the male can be 7 metres long, 3.2 metres tall at the shoulder and have a mass of 6500kg. Its tusks can weigh as much as 100kg each. The largest pair of tusks on record are in the British Museum and weigh 133kg each. What combination of animals could be equal to the elephant's weight?

For example, it takes 6500 ÷ 5 = 1300 big domestic cats to weigh 1 elephant or 130 big dogs.

How many rhinoceroses, lions, giraffes, or hippopotamuses weigh the same as an elephant?

Answers will vary depending on what other animals your students research.

Station 5: Mass of water

Measure out one litre (l) of water.

What is the mass of one litre of water? If 1L = 1000ml, what is the mass of 1mL of water?

For each container, estimate the capacity of the container, measure it to check, estimate the mass of water when the container is full, and find the mass of the water using scales.

Record your results like this:

How many drops of water are needed to fill each container?
What is the mass of a single drop?
1 litre (l) of water has a mass of 1 kilogram (1000 grams). 1 millilitre (mL) of water has a mass of 1 gram.

Answers depend on the size of the containers. Here is an example:

About 20 drops make 1 ml of water. Find the capacity of the container in mL then multiply by 20 to get the number of drops.
A single drop has a mass of 1/20 of 1g, that’s 0.05g.

Station 6: Frank’s arms

Counting on Frank by Rod Clement (1990; Harper Collins Publishers: Sydney) has some great ideas for measurement investigations. You can view readings of the book on YouTube if you cannot source a copy of the book. One of the ideas introduced in the story is about Frank carrying a trolley load of cans to the supermarket.

Trolleys measure 60 litres or 80 litres. What do those measures mean?
How heavy do you think Frank’s load of cans is?
How many cans are you able to carry in a reusable supermarket bag?

How did you work that out?

Here is another task based on Counting on Frank that you may choose to use.

1 litre is a unit of capacity, but it is also used as a unit of volume. One litre measures 10cm x 10cm x 10cm. 60 litres is 60 times that size.
Frank has 47 cans. They could be 420g cans so they would weigh 47 x 420g = 19 740g or 19.740 kg (about 20 kg). If the cans are bigger, say 820g, then the mass equals 47 times the mass of one can.
You could get 24 x 420g cans in a supermarket bag, or 36 cans if you add another layer. The mass of the bag would be 24 x 420g = 10.080 kg or 36 x 420g = 15.12 kg.

Dear family and whānau,

In class we have talked a lot about weight this week. In particular, we discovered that Konshiki, the largest Sumo wrestler, weighs 226kg, a Blue Whale weighs 180 tonnes and an elephant weighs 6500kg. What do you think the Blue Whale weighs in kg?

Your child has been asked to look for other facts associated with weight by reading the newspaper or doing some reading on the internet. They should record what they find out. Please encourage them to discuss their findings with you.

You could support them further by weighing items at home or cooking with them.

Figure It Out

Some links from the Figure It Out series which you may find useful are:

Measurement, Level 3-4: Can You, page 5; Breaking Bags, page 9; Egging you on, page 21
Sport, Level 3-4, Scrum Power, page 20
Measurement, Level 4: Taking Off, pages 6 & 7; Weighty Water, pages 12 & 13

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5 Newton’s Laws of Motion

5.4 Mass and Weight

Learning objectives.

By the end of the section, you will be able to:

Explain the difference between mass and weight
Explain why falling objects on Earth are never truly in free fall
Describe the concept of weightlessness

Units of Force

The equation [latex]{F}_{\text{net}}=ma[/latex] is used to define net force in terms of mass, length, and time. As explained earlier, the SI unit of force is the newton. Since [latex]{F}_{\text{net}}=ma,[/latex]

Weight and Gravitational Force

When an object is dropped, it accelerates toward the center of Earth. Newton’s second law says that a net force on an object is responsible for its acceleration. If air resistance is negligible, the net force on a falling object is the gravitational force, commonly called its weight [latex]\mathbf{\overset{\to }{w}}[/latex], or its force due to gravity acting on an object of mass m . Weight can be denoted as a vector because it has a direction; down is, by definition, the direction of gravity, and hence, weight is a downward force. The magnitude of weight is denoted as w . Galileo was instrumental in showing that, in the absence of air resistance, all objects fall with the same acceleration g . Using Galileo’s result and Newton’s second law, we can derive an equation for weight.

Consider an object with mass m falling toward Earth. It experiences only the downward force of gravity, which is the weight [latex]\mathbf{\overset{\to }{w}}[/latex]. Newton’s second law says that the magnitude of the net external force on an object is [latex]{\mathbf{\overset{\to }{F}}}_{\text{net}}=m\mathbf{\overset{\to }{a}}.[/latex] We know that the acceleration of an object due to gravity is [latex]\mathbf{\overset{\to }{g}},[/latex] or [latex]\mathbf{\overset{\to }{a}}=\mathbf{\overset{\to }{g}}[/latex]. Substituting these into Newton’s second law gives us the following equations.

The gravitational force on a mass is its weight. We can write this in vector form, where [latex]\mathbf{\overset{\to }{w}}[/latex] is weight and m is mass, as

In scalar form, we can write

Since [latex]g=9.80\,{\text{m/s}}^{2}[/latex] on Earth, the weight of a 1.00-kg object on Earth is 9.80 N:

Acceleration due to gravity g varies slightly over the surface of Earth, so the weight of an object depends on its location and is not an intrinsic property of the object. Weight varies dramatically if we leave Earth’s surface. On the Moon, for example, acceleration due to gravity is only [latex]{1.67\,\text{m/s}}^{2}[/latex]. A 1.0-kg mass thus has a weight of 9.8 N on Earth and only about 1.7 N on the Moon.

The broadest definition of weight in this sense is that the weight of an object is the gravitational force on it from the nearest large body, such as Earth, the Moon, or the Sun. This is the most common and useful definition of weight in physics. It differs dramatically, however, from the definition of weight used by NASA and the popular media in relation to space travel and exploration. When they speak of “weightlessness” and “microgravity,” they are referring to the phenomenon we call “free fall” in physics. We use the preceding definition of weight, force [latex]\mathbf{\overset{\to }{w}}[/latex] due to gravity acting on an object of mass m , and we make careful distinctions between free fall and actual weightlessness.

It is tempting to equate mass to weight, because most of our examples take place on Earth, where the weight of an object varies only a little with the location of the object. In addition, it is difficult to count and identify all of the atoms and molecules in an object, so mass is rarely determined in this manner. If we consider situations in which [latex]\mathbf{\overset{\to }{g}}[/latex] is a constant on Earth, we see that weight [latex]\mathbf{\overset{\to }{w}}[/latex] is directly proportional to mass m , since [latex]\mathbf{\overset{\to }{w}}=m\mathbf{\overset{\to }{g}},[/latex] that is, the more massive an object is, the more it weighs. Operationally, the masses of objects are determined by comparison with the standard kilogram, as we discussed in Units and Measurement . But by comparing an object on Earth with one on the Moon, we can easily see a variation in weight but not in mass. For instance, on Earth, a 5.0-kg object weighs 49 N; on the Moon, where g is [latex]{1.67\,\text{m/s}}^{2}[/latex], the object weighs 8.4 N. However, the mass of the object is still 5.0 kg on the Moon.

Clearing a Field

Significance

Check Your Understanding

For (Example) , find the acceleration when the farmer’s applied force is 230.0 N.

[latex]a=2.78\,{\text{m/s}}^{2}[/latex]

Mass is the quantity of matter in a substance.
The weight of an object is the net force on a falling object, or its gravitational force. The object experiences acceleration due to gravity.
Some upward resistance force from the air acts on all falling objects on Earth, so they can never truly be in free fall.
Careful distinctions must be made between free fall and weightlessness using the definition of weight as force due to gravity acting on an object of a certain mass.

Conceptual Questions

What is the relationship between weight and mass? Which is an intrinsic, unchanging property of a body?

How much does a 70-kg astronaut weight in space, far from any celestial body? What is her mass at this location?

Which of the following statements is accurate?

(a) Mass and weight are the same thing expressed in different units.

(b) If an object has no weight, it must have no mass.

(d) Mass and inertia are different concepts.

(e) Weight is always proportional to mass.

When you stand on Earth, your feet push against it with a force equal to your weight. Why doesn’t Earth accelerate away from you?

How would you give the value of [latex]\mathbf{\overset{\to }{g}}[/latex] in vector form?

The weight of an astronaut plus his space suit on the Moon is only 250 N. (a) How much does the suited astronaut weigh on Earth? (b) What is the mass on the Moon? On Earth?

a. [latex]\begin{array}{ccc}\hfill {w}_{\text{Moon}}& =\hfill & m{g}_{\text{Moon}}\hfill \\ \hfill m& =\hfill & 150\,\text{kg}\hfill \\ \hfill {w}_{\text{Earth}}& =\hfill & 1.5\times {10}^{3}\,\text{N}\hfill \end{array}[/latex]; b. Mass does not change, so the suited astronaut’s mass on both Earth and the Moon is [latex]150\,\text{kg.}[/latex]

Suppose the mass of a fully loaded module in which astronauts take off from the Moon is [latex]1.00\times {10}^{4}[/latex] kg. The thrust of its engines is [latex]3.00\times {10}^{4}[/latex] N. (a) Calculate the module’s magnitude of acceleration in a vertical takeoff from the Moon. (b) Could it lift off from Earth? If not, why not? If it could, calculate the magnitude of its acceleration.

A rocket sled accelerates at a rate of [latex]{49.0\,\text{m/s}}^{2}[/latex]. Its passenger has a mass of 75.0 kg. (a) Calculate the horizontal component of the force the seat exerts against his body. Compare this with his weight using a ratio. (b) Calculate the direction and magnitude of the total force the seat exerts against his body.

a. [latex]\begin{array}{ccc}\hfill {F}_{\text{h}}& =\hfill & 3.68\times {10}^{3}\,\text{N and}\hfill \\ \hfill w& =\hfill & 7.35\times {10}^{2}\,\text{N}\hfill \\ \hfill \frac{{F}_{\text{h}}}{w}& =\hfill & 5.00\,\text{times greater than weight}\hfill \end{array}[/latex];

b. [latex]\begin{array}{ccc}\hfill {F}_{\text{net}}& =\hfill & 3750\,\text{N}\hfill \\ \hfill \theta & =\hfill & 11.3^\circ\,\text{from horizontal}\hfill \end{array}[/latex]

Repeat the previous problem for a situation in which the rocket sled decelerates at a rate of [latex]{201\,\text{m/s}}^{2}[/latex]. In this problem, the forces are exerted by the seat and the seat belt.

A body of mass 2.00 kg is pushed straight upward by a 25.0 N vertical force. What is its acceleration?

[latex]\begin{array}{ccc}\hfill w& =\hfill & 19.6\,\text{N}\hfill \\ \hfill {F}_{\text{net}}& =\hfill & 5.40\,\text{N}\hfill \\ \hfill {F}_{\text{net}}& =\hfill & ma\Rightarrow a=2.70\,{\text{m/s}}^{2}\hfill \end{array}[/latex]

A car weighing 12,500 N starts from rest and accelerates to 83.0 km/h in 5.00 s. The friction force is 1350 N. Find the applied force produced by the engine.

A body with a mass of 10.0 kg is assumed to be in Earth’s gravitational field with [latex]g=9.80\,{\text{m/s}}^{2}[/latex]. What is its acceleration?

[latex]0.60\mathbf{\hat{i}}-8.4\mathbf{\hat{j}}\,{\text{m/s}}^{2}[/latex]

A fireman has mass m ; he hears the fire alarm and slides down the pole with acceleration a (which is less than g in magnitude). (a) Write an equation giving the vertical force he must apply to the pole. (b) If his mass is 90.0 kg and he accelerates at [latex]5.00\,{\text{m/s}}^{2},[/latex] what is the magnitude of his applied force?

When the Moon is directly overhead at sunset, the force by Earth on the Moon, [latex]{F}_{\text{EM}}[/latex], is essentially at [latex]90^\circ[/latex] to the force by the Sun on the Moon, [latex]{F}_{\text{SM}}[/latex], as shown below. Given that [latex]{F}_{\text{EM}}=1.98\times {10}^{20}\,\text{N}[/latex] and [latex]{F}_{\text{SM}}=4.36\times {10}^{20}\,\text{N},[/latex] all other forces on the Moon are negligible, and the mass of the Moon is [latex]7.35\times {10}^{22}\,\text{kg},[/latex] determine the magnitude of the Moon’s acceleration.

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Mass & weight

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Mass word problems

Word problem worksheets: mass and weight.

These word problems involve mass or weight. Problems involve the addition, subtraction, multiplication or division of amounts with units of mass . There are worksheets on both customary units (ounces & pounds) and metric units (gm, kg). Students are not asked to convert between the two systems.

Ounces, pounds:

Grams, kilograms:

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Worksheet on Word Problem on Measuring Mass

Practice the questions given in the worksheet on word problem on measuring mass (i.e. addition and subtraction). Addition and subtraction in grams and kilograms is done in the similar way as in the case of ordinary numbers.

1. Jason purchased 7 kg 200 g of sugar, 9 kg 395 g of rice. What is the total weight which Jason carried?

2. Rachel bought 8 kg 400 g tomatoes, 2 kg 130 g brinjal and 7 kg 300 g watermelon from the green grocer. How many kilograms of fruits and vegetables did she buy?

3. A rickshaw-puller is carrying two persons weighting 52 kg 250 g and 37 kg 700 g. What is the total weight of the two persons carried by the rickshaw-puller?

4. The total weight of Tania’s bag is 45 kg 750 g and Diana’s bag is 43 kg 950 g. Whose bag is heavier and by how much?

5. A truck was loaded with 352 kg 100 g of pumpkins and 207 kg 432 g of watermelons. Find the total weight carried by the truck.

6. Weight of a pile of English newspaper is 16 kg 270 g and that of French newspaper is 18 kg 227 g. If both the piles are tied together, what will be the total weight of the bundle?

7. A shopkeeper sold 67 kg 626 g of wheat on Saturday and 125 kg 200 g of wheat on Sunday. Find the total weight of wheat sold on both the days.

8. A grocer puts apples and plums together on the weighing machine. The total weight shown on the machine is 8 kg. If the weight of the plums is 2 kg 700 g, then what is the weight of the apples?

9. Jasmine purchased 7 kg 302 g of rice and Melissa purchased 3 kg 598 g more. What quantity of rice did Jasmine and Melissa purchase?

10. The weight of a chocolate carton is 20 kg. Each carton has 10 packets. Each packet has 25 chocolates. How many chocolates are there? Find the weight of each chocolate presuming that weight of carton and packets is negligible.

11. Brian sold 123 kg 231 g of newspapers and 200 kg of magazines. Find the total quantity of articles sold.

12. Ron takes care of deer and wild bulls in the zoo. The deer weighs 182 kg 290 g and a wild bull weighs 753 kg 380 g. Answer the given questions.

(i) If the both the animals stand on a weighing machine together what will be the total weight shown on the machine?

(ii) By how much is a bull heavier than deer?

(iii) If a deer eats 15 kg 250 g grass in a week. How much grass will be eaten by a deer in 42 days?

13. Aaron weight 49 kg 357 g and Ron weights 32 kg 458 g. Who weighs less and by how much?

14. If the total weight of 24 bulls having same weight is 487200 kg. What is the weight of each bull?

15. Father bought 10 kg 750 g of fruits (mangoes and apples). He had 6 kg 860 g of mangoes. What is the weight of apples?

16. Nina bought 5 kg of fruits. On the way home, she ate 750 g of fruits. How much fruit did she take back home?

17. Nancy brought a cake weighing 5 kg 675 g. Approximately 2 kg 395 g of cake is distributed among the children. What quantity of cake is left?

18. Rita weighs 13 kg 250 g. Her elder brother is three times heavier than Rita. What is her brother’s weight?

19. Mother purchased 9 kg 357 g of sweets and snacks for the occasion. Out of which 6 kg 458 g were consumed. What quantity of sweets and snacks were left?

20. A box can carry a total weight of 27 kg. Candies have to be packed inside the box. If the weight of each candy is 30 g, how many candies can be packed inside the box?

21. A shopkeeper purchased 287 kg 500 g of orange. Later on, he found that 98 kg 300 g of oranges were rotten. Find the quantity of oranges in good condition.

22. A lift can withstand a weight of 500 kg. There are 7 people standing to go in the lift. Given below are their weights. Find out if all of them can go inside the lift altogether. If no, then why?

$Word Problem on Measuring Mass$

23. Mary weighs 63 kg 59 g and Alex weighs 59 kg 36 g. Who weighs less and by how much?

24. Kellie’s weight is 55 kg 330 g. The doctor says that according to her height, her weight should be 62 kg. How much weight should she gain?

25. How much heavier is the toffee packet which has mass 1 kg 845 g in comparison to 500 g of chocolates?

Answers for the worksheet on word problem on measuring mass (i.e. addition and subtraction) are given below.

1. 16 kg 595 g

2. 17 kg 830 g

3. 89 kg 950 g

4. Tania’s bag is 1 kg 800 g

5. 559 kg 532 g

6. 34 kg 497 g

7. 192 kg 826 g

8. 5 kg 300 g

9. 10 kg 900 g

10. 250, 80 g

11. 323 kg 231 g

12. (i) 935 kg 670 g

(ii) 571 kg 90 g

(iii) 91 kg 500 g

13. Ron weighs less by 16 kg 899 g

14. 20,300 kg

15. 3 kg 890 g

16. 4 kg 250 g

17. 3 kg 280 g

18. 39 kg 750 g

19. 2 kg 899 g

$Worksheet on Word Problem on Measuring Mass$

21. 189 kg 200 g

22. All can go, 425 kg 350 g

23. Alex weighs less by 4 kg 23 g

24. 6 kg 670 g

25. 1 kg 345 g

Measurement of Mass:

What is Mass?

Conversion of Standard Unit of Mass

Conversion of Measuring Mass

Addition of Mass

Subtraction of Mass

Addition and Subtraction of Measuring Mass

Worksheet on Conversion of Mass

Worksheet on Addition of Mass

Worksheet on Third Grade Measurement of Mass

Worksheet on Subtraction of Mass

3rd Grade Math Worksheets

3rd Grade Math Lessons

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Physics Formulas

Weight Formula

Weight is not anything but the force gravity experiences. It is represented by W and Newton is its SI unit. It is articulated as the product of mass and acceleration due to gravity. So the weight of a given object will show variation according to the gravity in that particular space. So, objects with similar mass appear in different weights across different planets.

Formula of Weight

The formula for weight is articulated as,

W=mg

Weight of the object is W
Mass of the object is m
Acceleration due to gravity is g

Solved Examples

Numerical associated to weight calculations are provided underneath:

Problem 1: Compute the weight of a body on the moon if the mass is 60Kg? g is given as 1.625 m/s 2 . Answer :

It is known that, m = 60 kg and

g = 1.625 m/s 2

Formula for weight is, W = mg W = 60×1.625 W = 97.5 N

Problem 2: Compute the weight of a body on earth whose mass is 25 kg? Answer :

It is known that, m = 25 kg and

g = 9.8 m/s 2

Formula for weight is, W = mg W = 25×9.8 W = 245 N

Register with BYJU'S & Download Free PDFs

These are our mass and weight Word Problems worksheets for 2nd grade math school. Click on the previews to go to download page.

Worksheet by math grade levels:

Our grade 2 math worksheets are free and printable in PDF format. Based on the Singaporean math curriculum for second graders, these math worksheets are made for students in grade level 2. However, also students in other grade levels can benefit from doing these math worksheets. Feel free to print them. Our math worksheets cover important math topics such as: whole numbers, spelling, place value, skip counting, addition and subtraction, multiplication tables, basic division facts, fractions, mixed operations, geometry, graphing, picture graphs, measurement of time, mass, length and volume.

Our first grade math worksheets are free and printable in PDF format. Based on the Singaporean math school curriculum for grade 1 students, these 1st level math worksheets are made for students in school, tutoring or online math education. Our grade 1 math worksheets cover topics such as: whole numbers, spelling of basic numbers up to 10 or 100 and first grade math operations, grade 1addition and subtraction, place value, skip counting, introduction to division and multiplication, first grade geometry and basic shapes, easy picture graphs, length, volume and mass measurement and beginners number patterns.

IMAGES

Mass Problem Solving 2
problem solving about specific weight
Mass Activity For Grade 2 : Mass Problem Solving 2
Measuring mass: problem solving
Mass-to-Weight Problems Worksheet for 7th
Mass Problem Solving

VIDEO

Mass & Weight
Is mass always conserved? #chemistry #shorts #shortvideo
Mass and weight #shortsfeed
mass weight #science #pnysics #fun 😁
Difference between mass and weight. #mass&weight. #mass #weight @weight @mass
Weight Problem Secrets #healthcoach #weightloss

COMMENTS

Mass and weight
3. The mass of a box is 1 kg and acceleration due to gravity is 9.8 m/s 2. Find (a) weight (b) the horizontal component and the vertical component of the weight. Solution. Weight : w = m g = (1 kg)(9.8 m/s 2) = 9.8 kg m/s 2 = 9.8 Newton. The horizontal component of the weight :
5.4 Mass and Weight
Explain the difference between mass and weight; ... To apply Newton's second law as the primary equation in solving a problem, we sometimes have to rely on other equations, such as the one for weight or one of the kinematic equations, to complete the solution. ... [latex] {201\,\text{m/s}}^{2} [/latex]. In this problem, the forces are exerted ...
5.4 Mass and Weight
The equation Fnet = ma F net = m a is used to define net force in terms of mass, length, and time. As explained earlier, the SI unit of force is the newton. Since Fnet = ma, F net = m a, 1N = 1kg ⋅m/s2. 1 N = 1 kg · m/s 2. Although almost the entire world uses the newton for the unit of force, in the United States, the most familiar unit of ...
Mass and Weight
Mass and Weight. The Mass and Weight Concept Builder is a tool that challenges the learner to distinguish between the concepts of mass and weight. In addition to the conceptual aspect of these two concepts, students will also perform calculations of mass and weight. There are a total of 28 questions organized into nine different Question Groups ...
Mass and Weight
Weight Changes When (g) Changes. On Earth, your weight is caused by the earths pull on you. In a future lesson we will see that weight is the result of the your mass, the earths mass, and the distance between you and Earth. We will solve problems on this page using an average surface acceleration due to gravity
Mass and Weight Questions
Weight and mass are independent of any physical state of a matter, such as solid, gas, liquid, or plasma. Weight and mass have definite units and dimensions. Both mass and weight are measurable quantities. Weight and mass depend on the amount of matter in a body. 4. The mass of an object can be zero. True. False.
6.12: Mass and Weight
Be aware that weight and mass are different physical quantities, although they are closely related. Mass is an intrinsic property of an object: It is a quantity of matter. ... To apply Newton's second law as the primary equation in solving a problem, we sometimes have to rely on other equations, such as the one for weight or one of the ...
Weight
1 N. g. 9.8 m/s 2. m =. 0.102 kg = 102 g. The 96.7 gram tangerine comes closest to this value. Not all tangerines weigh 98.7 grams, however, so this is only a rule of thumb. There are certainly apples, bananas, oranges, tomatoes, and other fruits out there with a mass of approximately 102 grams and thus a weight of approximately one newton.
How to Calculate Weight from Mass: Formulas & Examples
The weight of an object equals the force of gravity exerted on that object. The mass of an object is always the same, but its weight changes depending on gravity. Use the formula. w = m ∗ g {\displaystyle w=m*g} to calculate weight from mass. In this formula, w {\displaystyle w} = weight (in N),
Word problems with mass (practice)
Word problems with mass. Emily needs 4 eggs for baking her cake. All of the eggs have the same mass. Emily knows the mass of 1 egg (shown below). What is the total mass of 4 eggs? Stuck? Review related articles/videos or use a hint. Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance ...
Mass and Weight (practice)
Course: UP Class 9th Science > Unit 9. Lesson 2: Week 2. Mass & weight. Mass and Weight. What is Pressure? Pressure and Buoyancy. Archimedes principle. Archimedes principle.
Converting Between Mass and Weight: Example Problems
Are mass and weight the same thing? This video explains the difference between mass and weight. This video also has four different example problems for how t...
Mass and Weight
Weight is the pull of Earth on an object. It depends on the distance from the center of Earth. Unlike weight, mass does not vary with location. The mass of an object is the same on Earth, in orbit, or on the surface of the Moon. Units of Force. The equation is used to define net force in terms of mass, length, and time.
Resources tagged with: Mass and weight
Resources tagged with: Mass and weight Types All types Problems Articles Games Age range All ages 5 to 11 7 to 14 11 to 16 14 to 18 Challenge level There are 20 NRICH Mathematical resources connected to Mass and weight , you may find related items under Measuring and calculating with units .
How to Solve Mass Conversion Problems
Notice on the scale: in order to change from grams to kilograms you have to move up. Therefore, we have to divide by 1,000: 1 kg = 1,000 g … then 600 g = 600 / 1000 kg … then 1,000 kg = 0.6 kg. Now we add: 2.25 kg + 0.6 kg = 2.85 kg. Thus, the answer to this problem is: At birth, Sara weighed 2.85 kg.
Word Problems Involving Mass and Weight
Total mass = 55 x 12 x 50 = 33000 g. 1000g = 1 kg = 33 kg. Example 2 : Find the total mass of 32 chocolates, each of mass 28 grams. Solution : Number of chocolates = 32. Mass of each chocolate = 28 grams. Total mass = 32 x 28 = 896 grams. Example 3 : If a clothes peg has a mass of 6.5 g, how many pegs are there in a 13 kg box? Solution :
Weighty Problems
Mass is the force created by gravity acting of on an object. Mass is felt as weight, a force that pulls the object towards the centre of the Earth. Mass is measured in units based on grams, and tonnes. Larger or smaller units are created by combining or equally partitioning these units. One kilogram is a combination of 1000 grams (kilo means 1000).
5.4 Mass and Weight
1.7 Solving Problems in Physics. 1 Chapter Review. 2 Vectors. Introduction. 2.1 Scalars and Vectors. 2.2 Coordinate Systems and Components of a Vector. 2.3 Algebra of Vectors. ... Explain the difference between mass and weight; Explain why falling objects on Earth are never truly in free fall;
Grade 4 mass and weight word problem worksheets
These word problems involve mass or weight. Problems involve the addition, subtraction, multiplication or division of amounts with units of mass. There are worksheets on both customary units (ounces & pounds) and metric units (gm, kg). Students are not asked to convert between the two systems. Ounces, pounds:
Mass and Weight
If the PDF does not show in the window above, then you can access it directly here: Mass and Weight (PDF) The Curriculum Corner contains a complete ready-to-use curriculum for the high school physics classroom. This collection of pages comprise worksheets in PDF format that developmentally target key concepts and mathematics commonly covered in ...
Worksheet on Word Problem on Measuring Mass
Answers for the worksheet on word problem on measuring mass (i.e. addition and subtraction) are given below. Answers: 1. 16 kg 595 g. 2. 17 kg 830 g. 3. 89 kg 950 g. 4.
Weight Formula With Solved Examples
Problem 1: Compute the weight of a body on the moon if the mass is 60Kg? g is given as 1.625 m/s 2. g = 1.625 m/s 2. Problem 2: Compute the weight of a body on earth whose mass is 25 kg? g = 9.8 m/s 2. The formula for weight is given as the product of mass and acceleration due to gravity. The solved numericals helps in understanding the formula ...
Grade 2 mass and weight Word Problems math school worksheets for
These are our mass and weight Word Problems worksheets for 2nd grade math school. Click on the previews to go to download page. Mass Problems (level 2) Mass Problems (level 2) Mass Problems (level 2) Worksheet by math grade levels: Grade 1 sheets. Grade 2 sheets. Grade 3 sheets. Grade 4 sheets.

Mass and weight – problems and solutions

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Discover more from Physics

5 Newton’s Laws of Motion

Units of Force

Weight and Gravitational Force

Clearing a Field

Significance

Check Your Understanding

Conceptual Questions

5.4 Mass and Weight

Units of Force

Weight and Gravitational Force

Example 5.8

Mass and Weight

Weight equals mass times gravity

Weight Changes When (g) Changes

Mass, Radius, and Acceleration due to Gravity of Planets

Mass, Radius, and Acceleration due to Gravity of Other Interstellar Objects

Normal Force Equals Weight on a Horizontal Surface

Problem Set

6.12: Mass and Weight

Learning Objectives

Units of Force

Weight and Gravitational Force

Defintion: Weight

Example \(\PageIndex{1}\): Clearing a Field

Exercise \(\PageIndex{1}\)

practice problem 1

practice problem 2

practice problem 3

How Find the Weight of an Object Using Mass and Gravity

Things You Should Know

Weight from Mass Calculation Help

Calculating Weight

Sample Problems

Catching Mistakes

Community Q&A

Addendum: Weights Expressed in kgf

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Mass and Weight

Units of Force

Weight and Gravitational Force

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