91Ó°ÊÓ

If all planets had the same average density, how would the acceleration due to gravity at the surface of a planet depend on its radius?

A rubber hose is attached to a funnel, and the free end is bent around to point upward. When water is poured into the funnel, it rises in the hose to the same level as in the funnel, even though the funnel has a lot more water in it than the hose does. Why? What supports the extra weight of the water in the funnel?

Redraw Fig. 3.11a if$\stackrel{\mathbf{→}}{\mathbf{a}}$is antiparallel to$\stackrel{\mathbf{→}}{\mathbf{v}}$. Does the particle move in a straight line? What happens to its speed?

If you heat the air inside a rigid, sealed container until its Kelvin temperature doubles, the air pressure in the container will also double. Is the same thing true if you double the Celsius temperature of the air in the container? Explain.

2. (a) Is it possible for an object to be in translational equilibrium (the first condition) but not in rotational equilibrium (the second condition)? Illustrate your answer with a simple example. (b) Can an object be in rotational equilibrium yet not in translational equilibrium? Justify your answer with a simple example.

Suppose you could use wheels of any type in the design of a soapbox-derby racer (an upward, four-wheel vehicle that costs from rest down a hill). To confirm the rules on the total weight of the vehicle and rider, should you design with large massive wheels or small light wheels? Should you use solid wheels or wheels with most of the mass at the rim? Explain.

Think of several examples in everyday life of motions that are, at least approximately, simple harmonic. In what respects does each differ from SHM?

Suppose you catch a baseball and then someone invites you to catch a bowling ball with either the same momentum or the same kinetic energy as the baseball. Which would you choose? Explain.

An elevator is hoisted by its cables at constant speed. Is the total work done on the elevator positive, negative, or zero? Explain.

Suppose you are asked to compute the tangent of 5.00meters. Is this possible? Why or why not?