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

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

16) Initially stationary, a train has a constant acceleration of 0.8 m/s².

(a) What is its speed after 32 s? (b) What is the total time required for the train to reach a speed of 38 m/s?

18) A skydiver jumps out of a helicopter and falls freely for 8.0 s before opening the parachute. (a) What is the skydiver's downward velocity when the parachute opens? (b) How far below the helicopter is the skydiver when the parachute opens?

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