CHAPTER 12 Assessment

Reviewing Content

Choose the letter that best answers the question or completes the statement.

1. Which is not a force?

   • friction

   • gravity

   • momentum

   • weight

2. You push on a box and are unable to move it.3 N8 N What force opposes your push?

   • static friction

   • rolling friction

   • sliding friction

   • air resistance

3. Air resistance depends on

   • the velocity of a moving object.

   • the weight of a moving object.

   • the mass of a moving object.

   • the inertia of a moving object.

4. What force besides gravity acts on a projectile?

   • weak nuclear

   • electrical

   • magnetic

   • air resistance

5. Newton's first law of motion is sometimes called the law of

   • inertia.

   • conservation.

   • momentum.

   • resistance.

6. A change in which of the following affects the weight of an object?

   • momentum

   • velocity

   • acceleration due to gravity

   • friction

7. Which represents Newton's second law?

   • $V=\genfrac{}{}{0.1ex}{}{d}{t}$

   • $a=\genfrac{}{}{0.1ex}{}{F}{m}$

   • 

   • 

8. For every action force there is a

   • reaction force.

   • net force.

   • friction force.

   • unbalanced force.

9. Momentum depends upon

   • force only.

   • velocity and friction.

   • weight and mass.

   • mass and velocity.

10. What force holds the nucleus together?

    • magnetic

    • strong nuclear

    • gravitational

    • centripetal greater momentum?

Understanding Concepts

11. Three forces act on a wooden crate that is initially at rest as shown below. Determine the net force acting on the crate and describe the resulting motion of the crate.

    

12. Suppose two 4-newton forces act on an object in the same direction. What is the net force on the object?

13. Five different forces act on an object. Is it possible for the net force on the object to be zero? Explain.

14. What happens to an object when an unbalanced force acts on it?

15. You push harder and harder on a box until it begins sliding across the floor. Which was the stronger of the forces acting on the box, static friction or sliding friction?

16. How do ball bearings reduce friction in machinery?

17. Explain why a falling object subjected to Earth's gravity does not continue to accelerate forever.

18. What is the difference between mass and weight?

19. What is an action-reaction pair?

20. What must you know to determine which of two vehicles traveling at the same velocity, has the

21. What force is responsible for your socks sticking together after they have been in a clothes dryer?

22. What particles do the strong and weak nuclear forces act on?

23. What force is responsible for the orbits of the planets in the solar system?

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