4) What does the slope of a distance-versus-time graph represent physically?

velocity

displacement

time

acceleration

area

8) A hypnotist's watch hanging from a chain swings back and forth every 0.61 s. What is the frequency (in Hz) of its oscillation?

9) A quartz crystal vibrates with a frequency of 95,621 Hz. What is the period of the crystal's motion?

10) A passenger jet flies from one airport to another 1,253 miles away in 2.2 h. Find its average speed.

11) How far does a car going 21 m/s travel in 8 s? How far would a jet going 165 m/s travel in 8 s?

13) A child attaches a rubber ball to a string and whirls it around in a circle overhead. If the string is 0.6 m long and the ball's speed is 16 m/s, what is the ball's centripetal acceleration?

14) During a NASCAR race a car goes 86 m/s around a curved section of track that has a radius of 240 m. What is the car's acceleration?

15) A rocket accelerates from rest at a rate of 56 m/s². 15A) What is its speed after it accelerates for 29 s? 15B) How long does it take for the rocket to reach a speed of 6,900 m/s?

19) A person is walking north on a sidewalk at about 3.15 mph. At the same time the wind is blowing from the north (toward the south) at about 2.65 mph. What relative wind speed will the person sense?

5.80 mph; the sum of the wind speed and the walking speed

3.15 mph; the greater of the two speeds

2.65 mph; the lesser of the two speeds

0.50 mph; the difference in the two speeds

20) A ball thrown at a brick wall approaches the wall at +41 m/s and, after striking the wall, bounces back at 41 m/s. What change in velocity did the ball experience?

+82 m/s

82 m/s

41 m/s

0.0 m/s

21) A swimmer in a river is chatting with a friend who is on the river bank. If the river current is flowing at 0.297 mph to the east, with what velocity relative to the water would the swimmer need to swim in order to remain in place relative to the person on shore?

0.297 mph to the east

0.297 mph to the north

0.297 mph to the west

0.594 mph to the west

22) A ball rolls up a ramp, getting slower and slower before rolling back to the bottom of the ramp. At the exact point where the ball transitions from rolling upward to rolling downward, how would you describe its velocity and its acceleration?

Neither the ball's velocity nor acceleration is zero.

The ball's velocity is zero, but its acceleration is not zero.

The ball's velocity is not zero, but its acceleration is zero.

Both the ball's velocity and acceleration are zero.

23) In the absence of air resistance, which of the following best describes the motion of a freely falling object near the surface of the Earth? (Assume the downward direction is positive.)

The velocity stays constant but the acceleration increases as the object falls.

The velocity increases but the acceleration remains constant as the object falls.

The velocity and the acceleration both increase as the object falls.

The velocity and the acceleration both stay constant as the object falls.

24) A student driver practicing in an empty parking lot is driving clockwise in a large circle at a constant speed. Is the car traveling with a constant velocity or is it accelerating?

The car has a constant speed, so the velocity is constant and there is no acceleration.

Since the car is changing direction as it travels around the circle, it has a centripetal acceleration and does not have a constant velocity.

25) What information is given by the slope of a distance vs. time graph?

the change in distance

the amount of time that has passed

the velocity

the acceleration