**Circular Motion and Simple Harmonic Motion**

Simultaneous shadow projection of circular motion and bouncing weight on spring.

### What It Shows

One of the simplest of periodic motions is uniform circular motion. By shadow projecting both uniform circular motion and oscillatory simple harmonic motion onto a screen, one can show that these two seemingly different kinds of motion are actually identical.

### How It Works

A 8 cm diameter plastic ball mounted near the edge of a 46 cm diameter disk undergoes uniform circular motion. The disk, oriented vertically, is driven by a 57 RPM motor.^{1} A large...