1. If the net force on a system is zero, is
the net torque also zero? If the net torque on a system is zero, is the net
force zero? Give examples.
2. Explain how a child pumps on a swing
to make it go higher.
3. Describe the torque needed if the person
in Fig. 1117 is to tilt the axle of the rotating wheel directly upward without
it swerving to the side.