RADT Physics Concepts Chapter 2 Describing Motion Test Bank Key

A car moving initially at 20 m/s comes gradually to a stop in 400 m. What was the acceleration of the car?

-0.5 m/s^2

A car 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

-5 m/s^2

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 45 m/s.

5

In order to go from rest in 100 m/s, a jet must be able to accelerate at

5 m/s^2

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

between 5.0 m and 1.0 m

Which of the following is not an appropriate unit for measuring acceleration? a. miles/hr/s b. ft/s^2 c. m/s d. km/min/s e. m/min^2

c. m/s

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

decreases very slowly.

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

displacement

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

speed.

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/s^2 is

zero.

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.

0

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

0.25 m/s

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

0.25 m/s^2

A speed of 200 km/hr is equivalent to _____ mph

124

If your average speed for a 3-hour trip is 45 mph, the distance traveled is

135 mi

A car starts from rest and reaches 20 m/s in 10 seconds. The average acceleration of the car in m/s^2 is

2.0

If your car can accelerate at 9.8 m/s^2, you can go from zero to 60 mph in about

2.74 s

A car is decelerating at the rate of 3 km/s^2. If its initial speed is 66 km/s, how long will it take the car to come to a complete stop?

22 s

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

25 ft/s^2

A sprinter moving at 10 m/s slows down at a rate of 1.4 m/s^2. How fast is the runner moving after 3 seconds?

3.7 m/s

An auto, starting from rest, undergoes constant acceleration and covers a distance of 1200 meters. The final speed of the auto is 60 meters/sec. How long does it take the car to cover 1200 meters?

40 s.

A car travels at 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

53.3 km/hr

A body travels at an initial speed of 1.5 m/s. Given a constant acceleration of 0.2 m/s^2, what is the speed of the body at a time 25 seconds later?

6.5 m/s

Initially you are driving at 55 mph. If you come to rest in 7.5 s while traveling 450 ft, your average speed is

60 ft/s

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

60.0 km/hr

A car accelerates uniformly. It starts from rest and reaches 24 m/s after 6.0 seconds. During the 6.0 seconds it has traveled _____ m.

72

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.

Change of direction at a constant speed means a change in velocity.

The following quantities relate to the rate of change of position. Which pair will always have the same magnitude?

Instantaneous speed and instantaneous velocity.

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

acceleration.

Which of the following quantities relating to motion is not a vector? a. displacement b. speed c. velocity d. acceleration e. all of these are vectors

b. speed

A car traveling at constant speed

can change direction.

In a speedometer test zone on a highway, you drive 5 miles in 6 minutes. During the test, your speedometer reading is 55 mph. Your speedometer reading is

higher than your actual speed

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

his total distance covered divided by the time.

Suppose a body sliding down a ramp is accelerating at a constant rate. Its speed will ________ the same amount each second.

increase

From a graph of speed versus time, for a body sliding down a ramp, one can get the ________ _________ from the slope of the curve.

instantaneous acceleration.

The velocity of a body is graphed as a function of time. The slope of the graph at any point may be identified with

instantaneous acceleration.

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

instantaneous velocity

A car rolls down a incline starting from rest. A graph of position versus time is made for this motion. One can get the

instantaneous velocity from the slope of the graph.

You travel 2640 feet in thirty seconds while in a 55 mph zone. Your average speed is

larger than the speed limit

There is a special racetrack that is all curve and no straightaway. If a driver takes her car around this track counterclockwise and at a constant speed, then the maximum acceleration will take place where the turning radius is

smallest.

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

the instantaneous velocity is positive but decreasing.

A car is driven between two nearby towns at an average speed of 50 mph. The magnitude of the average velocity of the car

will be the same as or less than the average speed.