2. Why is there no atmosphere on the moon?

3. Why is the pressure in an automobile's tires slightly greater after the car has been driven several kilometers?

12. Why do you suppose that airplane windows are smaller than bus windows?

25. Why is it so difficult to breathe when snorkeling at a depth of 1 m, and practically impossible at a 2-m depth? Why can't a diver simply breathe through a hose that extends to the surface?

44. What provides the lift to keep a Frisbee in flight?

54. What physics principle underlies these three observations? When passing an oncoming truck on the highway, your car tends to sway toward the truck. The canvas roof of a convertible automobile bulges upward when the car is traveling at high speeds. The windows of older trains sometimes break when a high-speed train passes by on the next track.