Chapter 2 Physics

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

93

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

A. -0.5 m/s2

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.

A. 16 ft/s2.

Which of the following quantities relating to motion is not a vector? A. Speed B. Velocity C. Acceleration D. All of these choices are

A. Speed

Acceleration represents the A. change in velocity with respect to time. B. change in distance with respect to time. C. product of velocity and time. D. product of distance and time.

A. change in velocity with respect to time.

A car moves along a straight section of road so that its velocity varies with time as shown in the graph. At which of the labeled points on the graph, A, B, or C, is the magnitude of the acceleration greatest? A. during segment A B. during segment B C. during segment C D. the acceleration is equal during all segments

A. during segment A

In which situation is the average speed most likely to be equal to the instantaneous speed? A. in free-flowing, low-density traffic B. in high density traffic C. in city driving

A. in free-flowing, low-density traffic

Refer to the graph. The object moves forward A. in region A. B. in region B. C. in regions A and C. D. The object always moves forward E. The object never moves forward

A. in region A.

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.

A. lower than your actual speed.

A driver steps on the brakes, causing the velocity of the car to decrease. Which of the following statements is correct? A. the driver has accelerated B. the driver has traveled with a constant velocity C. the driver has not accelerated D. the driver has kept their speed constant

A. the driver has accelerated

At which end of a traffic jam is the vehicle density lowest? A. the front end B. the back end C. In the middle

A. the front end

At which end of a traffic jam is the vehicle density lowest? A. the front end B. the back end C. in the middle

A. the front end

A racing sports car traveling with a constant velocity of 100 MPH due west startles a turtle by the side of the road who begins to move out of the way. Which of these two objects is likely to have the larger acceleration at that instant? A. the car B. the turtle C. neither are accelerating D. both must have the same acceleration

B. the turtle

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.

D. -2.5 m/s2.

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.

D. 360 mi.

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.

D. 4.0 m/s2.

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

D. 60 ft/s

A hockey puck is sliding on frictionless ice. It slams against a wall and bounces towards the player. In which of the following cases has the puck's velocity changed? A. if the ball comes back with the same speed it left with B. if the ball comes back with more speed than it left with C. if the ball comes back with less speed than it left with D. All of these choices are correct.

D. All of these choices are correct.

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. Instantaneous speed and instantaneous velocity

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

D. an object moving forward.

Suppose that critters are discovered on Mars who measure distance as boogles and time in bops. Which of the following would be their unit of speed? A. bop per boogles B. boogles per second C. bop boogles D. boogles per bop E. meters per bop

D. boogles per bop

A car moves along a straight line so that its position (distance from some starting point) varies with time as described by the graph shown here. For the car whose distance is plotted against time in the figure, when is the velocity constant? A. during segment A B. during segment B C. during segment C D. during all segments E. it is not constant during any segments

D. during all segments

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. instantaneous acceleration.

Which of the following best describes the term "vehicle density"? A. mass of vehicles per volume B. number of vehicles per volume C. mass of vehicles per distance D. number of vehicles per distance

D. number of vehicles per distance

A ball tied to a string fastened at the other end to a rigid support forms a pendulum. A. the velocity is constant but the speed is changing B. the speed is constant but the velocity is changing C. the speed and velocity are constant D. the speed and velocity are changing

D. the speed and velocity are changing

In the case of uniform accelerated motion, the graph of distance traveled versus time is a straight line TRUE OR FALSE

False

In the case of uniform accelerated motion, the graph of velocity versus time is a straight line. TRUE OR FALSE

True

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.

instantaneous acceleration

Suppose that the acceleration of a car increases with time. Could we use the relationship v = v_0 + at in this situation?

no

The velocity-vs-time graph of an object curves as shown in the diagram. Is the acceleration of the object constant?

no

For a uniformly accelerated car, is the average acceleration equal to the instantaneous acceleration?

yes

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

1

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.

10

A car moves along a straight line so that its position (distance from some starting point) varies with time as described by the graph shown here. How does the instantaneous velocity at point A compare with the instantaneous velocity at point B? A. they are the same B. it is larger at A C. it is larger at B D. there is no information about the velocity

B. it is larger at A

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

B. 4.4 m/s

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.

B. 5 m/s2.

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

B. 50 s

Speed is A. a vector quantity. B. a scalar quantity.

B. a scalar quantity.

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.

B. between 6.0 m/s and 2.0 m/s.

Suppose that critters are discovered on Mars who measure distance as boogles and time in bops. Which of the following would be their unit of velocity? A. bop per booglesIncorrect B. boogles per bop C. bop boogles D. meters per bop E. boogles per second

B. boogles per bop

A car moves along a straight section of road so that its velocity varies with time as shown in the graph. In which equal time segment is the distance traveled by the car the greatest? A. during time segment 0-2 seconds B. during time segment 2-4 seconds C. during time segment 4-6 seconds D. the distance traveled is equal during all segments

B. during time segment 2-4 seconds

A tortoise and a hare cover the same distance in a race. The hare goes very fast for brief intervals, but stops frequently, whereas the tortoise plods along steadily and finishes the race ahead of the hare. Which of the two racers is likely to reach the greatest instantaneous speed during the race A. tortoise B. hare

B. hare

Under what traffic conditions is the average speed of several vehicles equal to the average speed of the individual vehicles within the group? A. low density, fast moving, highway traffic B. high density highway traffic jam C. stop and go city traffic

B. high density highway traffic jam

Refer to the graph. The magnitude of the acceleration of the object is largest A. in region A. B. in region B. C. in region C. D. The object does not accelerate

B. in region B.

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.

B. instantaneous velocity.

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.

C. 33 s.

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.

C. 50.0 km/hr.

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.

C. 60.0 km/hr.

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

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

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.

C. acceleration

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.

C. can change direction.

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.

C. decreases very slowly.

Average speed is calculated by A. dividing the elapsed time by the distance traveled. B. multiplying distance traveled by the elapsed time. C. dividing the distance traveled by the elapsed time D. dividing the acceleration by the elapsed time.

C. dividing the distance traveled by the elapsed time.

A car traveling in the forward direction experiences a negative uniform acceleration for 10 seconds. The distance covered by the car in the first 5 seconds is _____ the distance covered by the car during the second 5 seconds. A. less than B. equal to C. greater than

C. greater than

A car moves along a straight line so that its position (distance from some starting point) varies with time as described by the graph shown here. When does the car go backwards? A. segment A B. segment B C. segment C D. never

C. segment C

Refer to the graph. The acceleration of the object is equal to zero A. in region A. B. in region B. C. in region C. D. in regions A and C. E. The acceleration is never equal to zero

E. The acceleration is never equal to zero

A car moves along a straight section of road so that its velocity varies with time as shown in the graph. During which segment does the car go backwards? A. during segment A B. during segment B C. during segment C D. during all segments E. it does not go backwards during any segments

E. it does not go backwards during any segments

What units would have an appropriate size for measuring the rate at which fingernails grow? A. millimeters per seconds B. kilometers per seconds C. millimeters per days D. kilometers per days E. millimeters per months F. kilometers per months

E. millimeters per months

Suppose that we chose inches as our basic unit of distance and days as our basic unit of time. Would this be a good choice of units for measure the acceleration of an automobile?

No

The instantaneous velocity of a toy car traveling in a straight line is shown in the graph. At which of the following times is the car accelerating? (Check All That Apply) t = 10 st = 10 s t = 20 st = 20 s t = 30 st = 30 s t = 40 st = 40 s t = 50 st = 50 s

t = 20 st = 20 s t = 30 st = 30 s t = 50 st = 50 s