Untitled Document

Physics Demo Number: 173

Approximate

Run Time 5 Min

Hooke's Law With Conical Spring

Demo Description

One uses a conical tapered spring along with two 250 gm masses to produce two extended values of the length of the spring to verify that extension is indeed proportional to load for this system.

Scientific Principles

Hooke's Law holds for a conical spring subjected to appropriate added loads.

Equipment

Two locater rods
Tall demonstration stand with three multipurpose adapters attached
Conical Spring
Two 250 gm hooked masses
Big rod and hook-collar for top of spring.

Equipment Location

The locater rods, hooked masses, and conical spring stay in Kit(173) on [F-4-3].
Demonstration stands are opposite [H-2-x] column, and to the left of door into 4327. Their multipurpose adapters are on the vertical stand rods.
The rod and collar for top of spring come from the hardware shelf in [G-1-x] and [G-2-x] columns.

Instructions

The photo shows two dedicated small locater rods, used with one of the big vertical stands and two of its multi-purpose adapters. A third , bigger rod , from the hardware shelf is screwed into the third multi-purpose adapter to hold one end of the conical spring.

One may mark the position of the bottom end of the spring, when it has no load attached , with the upper locater rod.

Addition of a 250 gm mass to the bottom end of the spring results in the positioning of the lower locater rod.

Addition of a second 250 gm mass puts the bottom end of the spring at the position seen in the photo.

One can thus clearly see that the spring extension from its no-load equilibrium position is directly proportional to load and thus that Hooke's Law is indeed holding for this system.