chapter 2

On Mars, where air resistance is negligible, an astronaut drops a rock from a cliff and notes that the rock falls about d meters during the first t seconds of its fall. Assuming the rock does not hit the ground first, how far will it fall during the first 2t seconds of its fall? a. 4d b. 16d c. 8d d. 2d

a. 4d

A ball is thrown vertically upward from the surface of the earth. The ball rises to some maximum height and falls back toward the surface of the earth. Which of the following statements concerning this situation is true if air resistance is neglected? a. The ball is a freely falling body for the duration of its flight. b. The acceleration of the ball is zero when the ball is at its highest point. c. The velocity and acceleration of the ball always point in the same direction. d. As the ball rises, its acceleration vector points upward.

a. The ball is a freely falling body for the duration of its flight.

Complete the following statement: For an object moving at constant velocity, the distance traveled a. is the same for each second that the object moves. b. cannot be determined, even if the elapsed time is known. c. increases for each second that the object moves. d. decreases for each second that the object moves.

a. is the same for each second that the object moves.

In which of the following situations is the displacement of the ball directly proportional to the elapsed time? a. the ball rolls with constant velocity. b. a ball rolling uphill experiences a decreasing acceleration. c. a ball rolling with velocity, v, is given a constant acceleration. d. a ball at rest is given a constant acceleration.

a. the ball rolls with constant velocity.

Which one of the following situations is not possible? a. A body has zero velocity and non-zero acceleration. b. A body travels with a constant velocity and a time-varying acceleration. c. A body travels with a northward velocity and a northward acceleration. d. both (a) and (c)

b. A body travels with a constant velocity and a time-varying acceleration.

Suppose that an object is moving with constant acceleration. Which of the following is an accurate statement concerning its motion?a. In equal times its speed changes by unequal amounts. b. In equal times its velocity changes by equal amounts. c. In equal times it moves equal distances. d. The object is not moving; it is at rest.

b. In equal times its velocity changes by equal amounts.

The slope of a line connecting two points on a position versus time graph gives a. average acceleration b. average velocity c. displacement d. instantaneous velocity

b. average velocity

When is the average velocity of an object equal to the instantaneous velocity? a. only when the velocity is decreasing at a constant rate b. only when the velocity is constant c. always d. never

b. only when the velocity is constant

A car accelerates from 10.0 m/s to 24.1 m/s at a rate of 3.00 m/s2. How far does the car travel while accelerating? a. 399 m b. 226 m c. 80.1 m d. 133 m

c. 80.1 m

What shape do we expect for a graph showing the position of a motorcycle versus time if the motorcycle is speeding up with a constant acceleration? a. The position versus time graph is a line with a positive slope. b. The position versus time graph is a horizontal line. c. The position versus time graph is parabolic. d. The position versus time graph is a line with a negative slope.

c. The position versus time graph is parabolic.

Which of the following statements must be true if the expression x = 0.5(v+vo)t is to be used? a. v is constant. b. x is constant. c. a is constant. d. air resistance must be taken into account.

c. a is constant.

Which of the following can cause a car to have an acceleration? a. The brakes on the car. b. The steering wheel. c. the gas pedal d. all of these

d. all of these

A rock is released from rest from a hot air balloon that is at rest with respect to the ground a few meters below. If we ignore air resistance as the rock falls, which one of the following statements is true? a. The rock is considered a freely falling body after it is released. b. As the rock falls, its acceleration is 9.8 m/s2, directed downward. c. After the ball is released it falls at a constant rate of 9.8 m/s every second. d. all of these.

d. all of these.

Which of the following quantities is defined as the distance traveled divided by the elapsed time for the travel? a. average acceleration b. average velocity c. instantaneous velocity d. average speed

d. average speed

The slope of a tangent line at a given time value on a velocity versus time graph gives a. average velocity. b. instantaneous velocity. c. average acceleration. d. instantaneous acceleration.

d. instantaneous acceleration.