PURPOSE: To show that 1-D SHM can be resolved from the component projection of 2-D UCM.
DESCRIPTION: A turntable platter rotates with UCM. The platter has a ping pong ball attached to it to act as a visual aid. Above the ping pong ball is the bob of a simple pendulum. The length of the pendulum string has a period that exactly matches the frequency of the turntable. The photo at right below shows that the phase of the pendulum can be synchronized to match the phase of the turntable by adjusting the rotating the platform.
Shadow project the image of the two synchronized motions with a carbon arc lamp.
EQUIPMENT: Turntable and ball, simple pendulum, rotating platform stand, arc lamp, portable screen.
SETUP NOTES: This is a rather long set up. A pendulum length of 78 cm is fine tuned to match the 33 rpm. Carefully adjusting the string length to exactness. Also, the arc lamp must be angled carefully to put the image onto the overhead screen. Synchroniz the pendulum with the rotating stand. Warm up the arc lamp before class so it will refire quickly.
Updated by Jun Qi in 3/24/2000