Name:    Test: Chapter 3

Multiple Choice
Identify the choice that best completes the statement or answers the question.

1

The weight of a person can be represented by a vector that acts
 a. straight down, even if the person is standing on a hill. b. parallel to the ground. c. in a direction that depends on where the person is standing. d. perpendicular to the ground underneath the person. e. all of the above

2

Compared to its mass on Earth, the mass of a 10-kg object on the moon is
 a. less. b. more. c. the same.

3

A 15-N force and a 55-N force act on an object in opposite directions. What is the net force on the object?
 a. 40 N b. 70 N c. 15 N d. 55 N e. none of the above

4

A 8-N force and a 26-N force act in the same direction on an object. What is the net force on the object?
 a. 26 N b. 18 N c. 34 N d. 8 N e. none of the above

5

Compared to its weight on Earth, a 10-kg object on the moon will weigh
 a. less. b. more. c. the same amount.

6

A gymnast whose weight is 520 N hangs from the middle of a bar supported by two vertical strands of rope. What is the tension in each strand?
 a. 520 N. b. 780 N. c. 260 N. d. 0 N. e. 1040 N.

7

What is the minimum resultant possible when adding a 2-N force to an 8-N force?
 a. 6 N b. 10 N c. 8 N d. 16 N e. 2 N

8

One object has twice as much mass as another object. The first object also has twice as much
 a. velocity. b. inertia. c. gravitational acceleration. d. all of the above

9

What is the maximum resultant possible when adding a 2-N force to a 11-N force?
 a. 11 N b. 13 N c. 9 N d. 22 N e. 2 N

10

The law of inertia states that an object
 a. will continue moving in a straight line unless an outside force acts on it. b. that is not moving will never move unless a force acts on it. c. at rest will remain at rest unless acted on by an outside force. d. will continue moving at the same velocity unless an outside force acts on it. e. will do all of the above.

11

How much does a 1.0-kg bag of nails weigh?
 a. 19.6 N b. 2.4 N c. 7.6 N d. 9.8 N e. 4.8 N

12

Friction
 a. acts in a direction that opposes the motion of an object. b. is the name given to the force acting between surfaces sliding past one another. c. comes from microscopic bumps that act as obstructions to the object's motion. d. all of the above e. none of the above

13

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. The reason this can be done is that
 a. the milk carton has very little weight. b. the milk carton has inertia. c. gravity pulls very hard on the milk carton. d. none of the above

14

An object weighs 10 N on Earth. A second object weighs 10 N on the moon. Which has the greater mass?
 a. The one on Earth b. They have the same mass. c. The one on the moon d. Not enough information to say

15

Equilibrium occurs when
 a. all the forces acting on an object are balanced. b. the sum of the +x forces on an object equals the sum of the –x forces. c. the sum of the upward forces equals the sum of the downward forces. d. the net force on the object is zero. e. all of the above

16

The law of inertia applies to
 a. objects at rest. b. moving objects. c. both moving and nonmoving objects.

17

Which has more mass, a kilogram of feathers or a kilogram of iron?
 a. Neither—they both have the same mass. b. The feathers c. The iron

18

Friction is a force that always acts
 a. in the same direction as an object's motion. b. opposite to an object's motion. c. perpendicular to an object's motion.

19

The astronomer Copernicus publicly stated in the 1500s that Earth
 a. is the center of the solar system. b. is slowing down. c. revolves around the sun. d. does not move. e. moves in a straight line.

20

After a cannonball is fired into frictionless space, the amount of force needed to keep it going equals
 a. zero, since no force is necessary to keep it moving. b. one quarter the force with which it was fired. c. the same amount of force with which it was fired. d. one half the force with which it was fired. e. twice the force with which it was fired.