Chapter 2: Describing Motion

A car moving initially at 20 m/s comes gradually to a stop in 400 m. What was the acceleration of the car? A. -0.5 m/s2. B. - 5 m/s2. C. -10 m/s2. D. - 20 m/s2

A

A quantity that is a measure of how the distance traveled changes with time is A. displacement. B. speed. C. acceleration. D. momentum. E. velocity.

B

A car starts from rest and reaches 20 m/s in 10 seconds. The average acceleration of the car in m/s2 is: A. Zero B. 1.0 C. 2.0 D. 4.0 E. 10.0

C

A quantity that is a measure of how the velocity of a body changes with time is: A. Displacement. B. Speed. C. Acceleration. D. Momentum.

C

Which of the following is not an appropriate unit for measuring acceleration? A. miles/hr/s. B. ft/s2. C. m/s. D. km/min/s. E. m/min2.

C

The velocity of a body is graphed as a function of time. The slope of the graph at any point may be identified with A. instantaneous velocity. B. average velocity. C. instantaneous speed. D. instantaneous acceleration. E. average acceleration

D

Which of the following quantities relating to motion is not a vector? A. Velocity. B. Average velocity. C. Displacement. D. Speed. E. Acceleration.

D

A body is traveling at a speed of 25 m/min at time t. Given a constant acceleration of 5 m/min2, what is the speed of the body at time t + 15 min? A. 100 m/min. B. 40 m/min. C. 10 m/min. D. 125 m/min. E. 325 m/min.

A

A student releases a ball from rest on an inclined plane and measures that it travels a distance of 0.5 m in a time of 2.0 s. The average speed of the ball is A. 0.25 m/s. B. 0.5 m/s. C. 1.0 m/s. D. 2.0 m/s.

A

An auto, starting from rest, undergoes constant acceleration and covers a distance of 1000 meters. The final speed of the auto is 80 meters/sec. How long does it take the car to cover the 1000 meters? A. 25 s. B. 100 s. C. 32 s. D. 9.8 s.

A

In order to go from rest to 100 m/s in 20 s, a jet must be able to accelerate at A. 5 m/s2. B. 10 m/s2. C. 20 m/s2. D. 100 m/s2.

A

You travel 2640 feet in thirty seconds while in a 55 mi/hr zone. Your average speed is A. larger than the speed limit. B. exactly the speed limit. C. less than the speed limit.

A

uppose a graph of displacement of a body versus time is constructed. The slope of the graph at any point may be identified with A. instantaneous velocity. B. instantaneous acceleration. C. average acceleration. D. average speed.

A

A car is decelerating at the rate of 3 km/s2. If its initial speed is 66 km/s, how long will it take the car to come to a complete stop? A. 2.2 s. B. 22 s. C. 192 s. D. 220 s.

B

A car rolls down an incline starting from rest. A graph of position versus time is made for this motion. One can get the A. distance traveled from the slope of the graph. B. instantaneous velocity from the slope of the graph. C. acceleration from the slope of the graph. D. velocity from the area under the graph. E. acceleration from the area under the graph

B

A car travels a distance of 80 km. For the first 30 minutes it is driven at a constant speed of 80 km/hr. The motor begins to vibrate and the driver reduces the speed to 40 km/hr for the rest of the trip. The average speed for the entire trip is: A. 60.0 km/hr. B. 53.3 km/hr. C. 50.0 km/hr. D. 47.5 km/hr. E. 40.0 km/hr

B

A policeman walks on his beat back and forth. His average speed is determined from: A. his displacement divided by the time. B. his total distance covered divided by the time. C. time divided by his displacement. D. time divided by his total path covered.

B

A student plots data for the velocity of a body versus the time on a graph. The area under the curve on the graph may be identified as A. acceleration. B. displacement. C. average velocity. D. average speed.

B

If the braking distance for your car at a certain speed is 200 ft and, after reacting to a situation, you have managed to stop your car in 4.0 s, then the magnitude of the acceleration was A. 12.5 ft/s2. B. 25 ft/s2. C. 32 ft/s2. D. 50 ft/s2.

B

The tendency of an auto to maintain its velocity is called A. mass. B. inertia. C. momentum. D. speed

B

Two displacement vectors are added: one of length 2.0 m and one of length 3.0 m. Not knowing the respective directions, we can say that the length of the sum of the vectors will be A. 5.0 m. B. between 5.0 m and 1.0 m. C. between 5.0 m and 3.0 m. D. less than 1.0 m. E. 2.0 m.

B

A car is driven between two nearby towns at an average speed of 50 miles/hour. The magnitude of the average velocity of the car A. will always be the same as the average speed. B. will always be less than the average speed. C. will be the same as or less than the average speed. D. will be the same as or greater than the average speed. E. will always be greater than the average speed.

C

For the first hour a car is driven at a constant speed of 80 km/hr. The motor begins to vibrate and the driver reduces the speed to 40 km/hr for another hour. The average speed for the entire trip is: A. 80.0 km/hr B. 53.3 km/hr C. 60.0 km/hr D. 47.5 km/hr E. 40.0 km/hr

C

If your average speed for a 3-hr trip is 45 mi/hr, the distance traveled is A. 15 mi. B. 45 mi. C. 135 mi. D. 202.5 mi

C

If your car can accelerate at 32 ft/s2, you can go from zero to 60 mi/hr in about A. 0.533 s. B. 1.875 s. C. 2.75 s. D. 5.5 s

C

In a speedometer test zone on a highway, you drive 5 miles in 6 minutes. During the test, your speedometer reading is 55 mi/hr. Your speedometer reading is A. lower than your actual speed. B. equal to your actual speed. C. higher than your actual speed.

C

Initially you are driving at 55 mi/hr. If you come to rest in 5.0 s while traveling 200 ft, your average speed is A. 55 mi/hr. B. 27.5 mi/hr. C. 40 ft/s. D. 20 ft/s.

C

The acceleration of a body must be zero at a point where A. the instantaneous velocity is zero but changing. B. the instantaneous velocity is not zero but changing. C. the instantaneous velocity is constant.

C

A car is traveling at the velocity of 20 m/s on a flat road when it reaches the bottom of a hill. It coasts up the hill, coming to rest in 4 seconds. The average acceleration of the car while on the hill is A. 20 m/s2. B. 5 m/s2. C. 0 m/s2. D. -5 m/s2. E. -20 m/s2

D

A student releases a ball from rest on an inclined plane and measures that it travels a distance of 0.5 m in a time of 2.0 s. The acceleration of the ball is A. 0.125 m/s2. B. 0.25 m/s2. C. 0.5 m/s2. D. 1.0 m/s2.

D

The following quantities relate to the rate of change of position. Which pair will always have the same magnitude? A. Average speed and average velocity. B. Average speed and instantaneous speed. C. Average velocity and instantaneous velocity. D. Instantaneous speed and instantaneous velocity

D

An auto moves 10 meters in the first second of travel, 10 more meters in the next second and 10 meters during the third second. The acceleration of the auto in m/s2 is A. 3.33 B. 9.8 C. 30 D. 10 E. Zero.

E