Physics Demo Number: 142

Approximate

Run Time: 5 min

Small Torque, Large Kinetic Energy, Angular Motion

Demo Description

By mounting the heavy bike wheel on a big support stand with the help of a table clamp, one can demonstrate rotational motion that persists for several minutes.

Scientific Principles

• High rotational inertia and low frictional torque allows a steady rotational state to persist for an extended time interval: In essence, one is showing

• Newton's First Law for rotational motion.

Equipment

• The Heavy Bike Wheel

• Table Clamp

• Support Stand

Equipment Location

• [E-3-1] houses the wheel.

• Table clamps are on [G-2-4].

• The Support Stand is next to the door into 4327.

Instructions

The first photo shows the heavier angular momentum bike wheel mounted on a big support stand with the aid of a table clamp.

The second photo gives a closer look.

This wheel has low enough frictional torque and high enough rotational inertia to allow a brisk spin up by hand to continue for several minutes to illustrate angular motion with little angular acceleration. 

The following picture shows an axle robbed from an old cart complete with two attached wheels  .

This   can serve as a very nice example of a system  of three connected rigid bodies (axle plus wheel plus wheel ) that may be 

set spinning about its center of mass with no translational kinetic  energy of the center of mass.

Writeup created by David A. Burba

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