Shows relationship between SHM and circular motion.

===== Purpose ===== To show how simple harmonic motion and circular motion are related, by projecting the side on image of a ping pong ball moving in a circular fashion

===== Apparatus ===== Rotation machine Ping Pong ball duct taped to it Projector Screen Mass on Spring

===== Setup ===== Set up the screen. Hang the mass on a spring from the top of the screen. Turn on machine and project light past the machine onto the screen. Trying out some different masses and rotation speeds, it should be possible to get fairly good coincidence of the oscillatory motion of the spring, and that of the shadow of the ping pong ball. A mass of 800g and the fastest setting on the machine works fairly well.