# Force and Motion - Chapter No 5

Right Answers have been shown below in red color.

1. An example of an inertial reference frame is:

A. any reference frame that is not accelerating
B. a frame attached to a particle on which there are no forces
C. any reference frame that is at rest
D. a reference frame attached to the center of the universe
E. a reference frame attached to Earth

2. An object moving at constant velocity in an inertial frame must:

A. have a net force on it
B. eventually stop due to gravity
C. not have any force of gravity on it
D. have zero net force on it
E. have no frictional force on it

3. In SI units a force is numerically equal to the , when the force is applied to it.

A. velocity of the standard kilogram
B. speed of the standard kilogram
C. velocity of any object
D. acceleration of the standard kilogram
E. acceleration of any object

4. Which of the following quantities is NOT a vector?

A. Mass
B. Displacement
C. Weight
D. Acceleration
E. Force

5. A newton is the force:

A. of gravity on a 1 kg body
B. of gravity on a 1 g body
C. that gives a 1 g body an acceleration of 1 cm/s2
D. that gives a 1 kg body an acceleration of 1 m/s2
E. that gives a 1 kg body an acceleration of 9

6. The unit of force called the newton is:

A. 9.8 kg · m/s2
B. 1 kg · m/s2
C. defined by means of Newton’s third law
D. 1 kg of mass
E. 1 kg of force

6. The unit of force called the newton is:

A. 9.8 kg · m/s2
B. 1 kg · m/s2
C. defined by means of Newton’s third law
D. 1 kg of mass
E. 1 kg of force

7. A force of 1 N is:

A. 1 kg/s
B. 1 kg · m/s
C. 1 kg · m/s2
D. 1 kg · m2/s
E. 1 kg · m2/s2

8. The standard 1-kg mass is attached to a compressed spring and the spring is released. If the mass initially has an acceleration of 5.6 m/s2, the force of the spring has a magnitude of:

A. 2.8 N
B. 5.6 N
C. 11.2 N
D. 0
E. an undetermined amount

9. Acceleration is always in the direction:

A. of the displacement
B. of the initial velocity
C. of the final velocity
D. of the net force
E. opposite to the frictional force

10. The term “mass” refers to the same physical concept as:

A. weight
B. inertia
C. force
D. acceleration
C. volume

11. The inertia of a body tends to cause the body to:

A. speed up
B. slow down
C. resist any change in its motion
D. fall toward Earth
E. decelerate due to friction

12. A heavy ball is suspended as shown. A quick jerk on the lower string will break that string but a slow pull on the lower string will break the upper string. The first result occurs because: A. the force is too small to move the ball
B. action and reaction is operating
C. the ball has inertia
D. air friction holds the ball back
E. the ball has too much energy

13. When a certain force is applied to the standard kilogram its acceleration is 5.0 m/s2. When the same force is applied to another object its acceleration is one-fifth as much. The mass of
the object is:

A. 0.2 kg
B. 0.5 kg
C. 1.0 kg
D. 5.0 kg
E. 10 kg

14. Mass differs from weight in that:

A. all objects have weight but some lack mass
B. weight is a force and mass is not
C. the mass of an object is always more than its weight
D. mass can be expressed only in the metric system
E. there is no difference

15. The mass of a body:

A. is slightly different at different places on Earth
B. is a vector
C. is independent of the free-fall acceleration
D. is the same for all bodies of the same volume
E. can be measured most accurately on a spring scale

16. The mass and weight of a body:

A. differ by a factor of 9.8
B. are identical
C. are the same physical quantities expressed in different units
D. are both a direct measure of the inertia of the body
E. have the same ratio as that of any other body placed at that location

17. An object placed on an equal-arm balance requires 12 kg to balance it. When placed on a spring scale, the scale reads 12 kg. Everything (balance, scale, set of weights and object) is
now transported to the Moon where the free-fall acceleration is one-sixth that on Earth. The new readings of the balance and spring scale (respectively) are:

A. 12 kg, 12 kg
B. 2 kg, 2 kg
C. 12 kg, 2 kg
D. 2 kg, 12 kg
E. 12 kg, 72 kg

18. Two objects, one having three times the mass of the other, are dropped from the same height in a vacuum. At the end of their fall, their velocities are equal because:

A. anything falling in vacuum has constant velocity
B. all objects reach the same terminal velocity
C. the acceleration of the larger object is three times greater than that of the smaller object
D. the force of gravity is the same for both objects
E. none of the above

19. A feather and a lead ball are dropped from rest in vacuum on the Moon. The acceleration of the feather is:

A. more than that of the lead ball
B. the same as that of the lead ball
C. less than that of the lead ball
D. 9.8 m/s
2
E. zero since it floats in a vacuum

20. The block shown moves with constant velocity on a horizontal surface. Two of the forces on it are shown. A frictional force exerted by the surface is the only other horizontal force on the
block. The frictional force is: A. 0
B. 2 N, leftward
C. 2 N, rightward
D. slightly more than 2 N, leftward
E. slightly less than 2 N, leftward