MULTIPLE CHOICE.  Choose the one alternative that best completes the statement or answers the question.

1)  As an object freely falls downward, its

A) velocity increases. B)  acceleration increases.

C) both of these. D)  none of these.

2)  Whirl a rock at the end of a string on an ice-covered pond and it follows a circular path.  If the string breaks, the tendency of the rock is to

A) continue to follow a circular path. B)  follow a straight-line path.

3)  A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that

A) the milk carton has no acceleration.

B) there is an action-reaction pair of forces.

C) gravity tends to hold the milk carton secure.

D) the milk carton has inertia.

E) none of these.

4)  The gain in speed each second for a freely-falling object is about

A) 0.

B) 5 m/s.

C) 10 m/s.

D) 20 m/s.

E) depends on the initial speed.

5)  A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is

A) zero.

B) less than 30 m/s but larger than zero.

C) about 30 m/s.

D) more than 30 m/s.

E) more information needed for an estimate.

6)  A truck is moving at constant velocity.  Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below.  The rock hits the floor

A) exactly below the midpoint of the ceiling.

B) ahead of the midpoint of the ceiling.

C) behind the midpoint of the ceiling.

D) more information is needed to solve this problem.

E) none of these.

7)  If you are carrying a heavy bag of groceries and bang your hand against the wall, the concept that most explains why you are hurt is

A) inertia

B) gravity

C) acceleration

D) resistance

E) none of these

Figure 2-A

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8)  According to Newton's law of inertia, the result of walking much of the day is similar to tightening the head of a hammer when its handle hits a solid surface so that we are actually a little bit shorter in the

A) morning. B)  evening. C)  no difference, really.

9)  Whirl a rock at the end of a string and it follows a circular path.  If the string breaks, the tendency of the rock is to

A) continue to follow a circular path. B)  follow a straight-line path.

1)  Answer:  A

2)  Answer:  B

3)  Answer:  D

4)  Answer:  C

5)  Answer:  C

6)  Answer:  A

7)  Answer:  A

8)  Answer:  B