Projection of Uniform Circular Motion and Simple Harmonic Motion of a Spring

Attach the Ball-and-Spring combination to a ring stand.  Place the vertical-plane rotating motor next to the spring.  Place the illuminating slide projector about a meter away and project the images of the oscillating ball on the spring and rotating ball on a wall. Start the mass so that its oscillation is in phase with the driven ball.

Uniform Circular Motion describes the movement of an object traveling a circular path with constant speed. The one-dimensional projection of this motion can be described as simple harmonic motion.

A point P moving on a circular path with a constant angular velocity ω is undergoing uniform circular motion. Its projection on the x-axis undergoes simple harmonic motion. This can be compared with the projection of the linear vertical motion of an oscillating mass on a spring.