Untitled Document

Physics Demo Number: 156

Approximate

Run Time: 5 min

Horizontal (Compressional) Spring and Resonance

Demo Description

Use a dedicated apparatus for showing a real compressional spring and some of its possible excitations.

Scientific Principles

Resonant frequencies of mechanical systems involving springs.

Equipment

Dedicated self contained unit.

Equipment Location

On [E-3-6].

Instructions

The first photo shows the dedicated rod-spring-clamp system, attached to a shelf in [E-2] column.

The rod , associated linear bearing , and compressional spring were fabricated in the Science Shop.

The special table clamp can be turned over and attached directly to the lecture table.

A closer view of the moving linear bearing and clamp are provided in the second photo.

After setting the rod up horizontally on the lecture table, one may compress the spring and note a few oscillations of the plastic mass, before friction damps the motion out.

One may assert that the motion is (damped) SHM.

One has no conceptual effect of gravity problem to worry with explaining.

There are also none of the double spring hook-ups usually associated with extension and compression of a spring to worry about.

By placing a hand on the spring and inputting periodic horizontal pulses to the spring, one may show driven SHM of the plastic mass at about the resonant natural frequency of the spring-mass system.