Deck 2: Describing Motion

Question 1

In a speedometer test zone on a highway, you drive 4 miles in 5 minutes. During the test, your speedometer reading is 45 mi/hr. Your speedometer reading is

A) lower than your actual speed.
B) equal to your actual speed.
C) higher than your actual speed.

Answer 1

lower than your actual speed.

Question 2

The acceleration of a body cannot be zero at a point where

A) the instantaneous velocity is zero.
B) the instantaneous velocity is positive but decreasing.
C) the average velocity is positive.
D) none of these.

Answer 2

the instantaneous velocity is positive but decreasing.

Question 3

An auto, starting from rest, undergoes constant acceleration and covers a distance of 1250 meters. The final speed of the auto is 50 meters/sec. How long does it take the car to cover the 1250 meters?

A) 30 s
B) 50 s
C) 0.05 s
D) 72,000 s

Answer 3

50 s

Question 4

Initially you are driving at 55 mi/hr. If you come to rest in 7.5 s while traveling 450 ft, what is your average speed while stopping? (There are 5280 ft in one mi.)

A) 55 mi/hr
B) 0.016 ft/s
C) 120 ft/s
D) 60 ft/s

Question 5

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.

Question 6

You travel 2640 feet in thirty seconds while in a 65 mi/hr zone. (There are 5280 ft in one mi.) Your average speed is

A) larger than the speed limit.
B) exactly the speed limit.
C) less than the speed limit.

Question 7

An auto moves 10 meters in the first second of travel, 15 more meters in the next second, and 20 more meters during the third second. The acceleration of the auto is

A) 3.33 m/s².
B) 9.8 m/s².
C) 30 m/s².
D) 5 m/s².
E) zero m/s².

Question 8

In order to go from rest to 50 m/s in 10 s, a jet must be able to accelerate at

A) 2 m/s².
B) 5 m/s².
C) 20 m/s².
D) 50 m/s².

Question 9

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) average velocity.
C) average speed.
D) distance.

Question 10

A student releases a ball from rest on an inclined plane and measures that it travels a distance of 0.8 m in a time of 4.0 s. The average speed of the ball is

A) 3.2 m/s.
B) 1.0 m/s.
C) 0.2 m/s.
D) 2.0 m/s.

Question 11

A quantity that is a measure of how the velocity of a body changes with time is

A) distance.
B) speed.
C) acceleration.
D) time.

Question 12

A car traveling at constant speed

A) does not turn.
B) travels more distance in a second the longer the car travels.
C) can change direction.
D) cannot be going uphill.

Question 13

A policeman walks on his beat back and forth. His average speed is determined from

A) his velocity divided by the time.
B) time divided by how far he ends up from the starting point.
C) his total distance covered divided by the time.
D) time divided by his total distance covered.

Question 14

Suppose a graph of distance traveled by a body versus time is constructed. The slope of the graph at any point may be identified with

A) instantaneous acceleration.
B) instantaneous velocity.
C) average acceleration.
D) average speed.

Question 15

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 greater than the average speed.
D) will be the same as or less than the average speed.
E) will always be greater than the average speed.

Question 16

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 5.0 s, then the magnitude of the acceleration was

A) 16 ft/s².
B) 25 ft/s².
C) 32 ft/s².
D) 50 ft/s².

Question 17

If your average speed for a 6 hr trip is 60 mi/hr, the distance traveled is

A) 10 mi.
B) 60 mi.
C) 120 mi.
D) 360 mi.

Question 18

Your car can accelerate at 8.0 m/s², and there are 1609 m in one mile. So you can go from zero to 60 mi/hr in about

A) 3.35 s.
B) 2.74 s.
C) 1.34 s.
D) 0.37 s.

Question 19

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.

Question 20

A car travels a distance of 100 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.

Question 21

Two velocity vectors are added: one of magnitude 2.0 m/s and one of magnitude 4.0 m/s. Not knowing the respective directions, we can say that the magnitude of the sum of the vectors will be

A) 6.0 m/s.
B) between 6.0 m/s and 2.0 m/s.
C) between 6.0 m/s and 4.0 m/s.
D) less than 2.0 m/s.
E) 2.0 m/s.

Question 22

A car starts from rest and reaches 20 m/s in 5 seconds. The average acceleration of the car is

A) zero m/s².
B) 1.0 m/s².
C) 2.0 m/s².
D) 4.0 m/s².
E) 10.0 m/s².

Question 23

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.

Question 24

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 8 seconds. The average acceleration of the car while on the hill is

A) 10 m/s².
B) 2.5 m/s².
C) 0 m/s².
D) -2.5 m/s².
E) -10 m/s².

Question 25

A car driver takes Turn 1 at Daytona International Speedway at a steady 120 mph all the way through the turn. The radius of this turn is 1000 feet. Which statement is true?

A) Its velocity is constant because its speed is constant.
B) Its speed is constant so its acceleration is zero.
C) Change of direction at constant speed means a change in velocity.
D) Its velocity changes only if its speed decreases.
Refer to the diagram of Racetrack X.

Question 26

Refer to the graph above. The velocity of this object at the start of the motion is

A) positive.
B) zero (it is not moving).
C) negative.
D) It is not possible to tell from the graph.

Question 27

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.

Question 28

A quantity that is a measure of how the distance traveled changes with time is

A) speed.
B) force.
C) acceleration.
D) momentum.
E) velocity.

Question 29

Which of the following quantities relating to motion is not a vector?

A) Distance
B) Speed
C) Velocity
D) Acceleration
E) All of these are vectors.

Question 30

A sprinter moving at 10 m/s slows down at a rate of 1.4 m/s². How fast is the runner moving after 4 seconds?

A) 0 m/s.
B) 4.4 m/s.
C) 5.8 m/s.
D) 15.6 m/s.

Question 31

For the first hour a car is driven at a constant speed of 90 km/hr. The motor begins to vibrate and the driver reduces the speed to 45 km/hr for another 2 hours. The average speed for the entire trip is

A) 90.0 km/hr.
B) 25.5 km/hr.
C) 60.0 km/hr.
D) 67.5 km/hr.
E) 45.0 km/hr.

Question 32

An object moving at 30 m/s has an acceleration of -2.0 m/s/hr. Its speed

A) increases very quickly.
B) increases very slowly.
C) decreases very slowly.
D) decreases very quickly.

Question 33

A car is decelerating at the rate of 2 km/s². If its initial speed is 66 km/s, how long will it take the car to come to a complete stop?

A) 3.3 s.
B) 132 s.
C) 33 s.
D) 330 s.

Question 34

A body travels at an initial speed of 2.5 m/s. Given a constant acceleration of 0.2 m/s², what is the speed of the body at time 25 seconds later?

A) 3.4 m/s.
B) 3.6 m/s.
C) 5.5 m/s.
D) 6.0 m/s.
E) 7.5 m/s.

Question 35

Refer to diagram of billiard balls F, K, M, and T. Each arrow represents the velocity of the ball. If billiard ball M is traveling straight upward at 2.5 m/sec, then

A) billiard ball M must be faster than T.
B) billiard ball F is the slowest of the four.
C) billiard ball K has the same velocity as M.
D) nothing about their speeds can be said, because they are all moving in different directions.

Question 36

Refer to the graph above. For the entire motion, the average velocity is

A) positive.
B) zero (it is not moving).
C) negative.
D) It is not possible to tell from the graph.

Question 37

Refer to the speedometer in Figure 2.3. The speedometer reading 75 mph is

A) approximately 2 kilometers per minute.
B) exactly 1 mile per minute.
C) 200 meters per second.
D) the only speed at which mph and km/h are equal.

Question 38

An object's distance traveled as a function of time is shown in the graph above. The graph shows

A) an object experiencing an acceleration.
B) an object with increasing speed.
C) an object turning in a circle.
D) an object moving forward.

Question 39

A car moving initially at 30 m/s comes gradually to a stop in 900 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.

Question 40

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

Question 41

This special racetrack is all curve and no straightaway. If a driver takes her car around this track counterclockwise and at constant speed, then greater acceleration will occur at any place the turning radius is

A) larger.
B) smaller.
C) inward.
D) outward.

Question 42

From a graph of speed versus time, like Figure 2.15, for a body sliding down a ramp, one can get the _______________ ____________________ from the slope of the curve.

Question 43

A speed of 150 km/hr is equivalent to _________ mph. (There are 1.609 km in a mile.)

Question 44

A car starts from rest and after 10 seconds is traveling at 30 m/s. Assuming that it continues to accelerate at the same rate it will take another ________ seconds to reach 60 m/s.

Question 45

If you are traveling 80 mph, how many hours does it take you to go 80 miles?

Question 46

Suppose a body sliding up a ramp is decelerating at a constant rate. Its speed will __________ by the same amount each second.

Question 47

Refer to the diagram of Racetrack X. It is ________ for a racer to have uniform acceleration ________ on this track.

A) impossible; anywhere
B) impossible; at some places
C) possible; everywhere
D) guaranteed, at some places
Fill in the Blank Questions

Question 48

The tip of the second hand of a clock moves in a circle of 20 cm circumference. In one minute the hand makes a complete revolution. Its average velocity over that time is ___________ cm/s.

Question 49

A car accelerates uniformly. It starts from rest and reaches 36 m/s after 6.0 seconds. During the 6.0 seconds it has traveled _______________ m.