Warm-Up Exercise for lecture 25

Due 8:00 am, Tues, Dec 2

Physics 105, Fall 2008

Some object is moving back and forth in harmonic motion. Where is the acceleration of that object greatest?
☐ at the midpoint of the motion
☑ at the end points of the motion
☐ same value at every point

Consider a mass m hanging on a spring. We pull the mass downward and then release it so that it oscillates up and down. If we repeat this on the moon with the same mass and the same spring, the frequency of the oscillation will be:
☐ larger
☐ smaller
☑ the same

Two students play with an extra-long Slinky. The student on the left end sends waves to the other student by shaking her end back and forth. After the waves die down, both students take a step backwards and try it again. How will the speed of the waves now compare to the previous waves?
☑ They will be faster
☐ They will be slower
☐ They will go the same speed

Ralph is confused about pendulums. He read in the textbook that the period T of a pendulum depends on its length L and on the acceleration of gravity g,but does not depend on its mass. Ralph thinks that heavier pendulums should swing with a longer period. After all, if he puts a heavier weight on the end of the spring, it oscillates more slowly. Can you help Ralph understand this?
The "restoring force" is provided by gravity (by a component, at least), and so is proportional to mass. Since the acceleration is equal to F/m, the masses cancel out. This is the same reason that all objects fall at the same rate.