1Q40.40 • Conservation of Angular Momentum: Conservation of Angular Momentum Using a Point Mass

Location: Cabinet 1

Photo shows the demonstration used at the University of Texas at Austin.

Concept conveyed:

Instructions:

Place the track on the base, tightening the screw, and attach the spring pulley so that the spring is centered on the 0 cm mark.
Put one of the 300 g masses on the left side of the track leaving it loose by not tightening the screw on the top, about at the 10 cm mark.
Make sure the side of the mass with the hole is facing the center of the track.
Put the stop screws at about the 3 and 24 cm marks making sure to securely tighten them so they do not move.
Take the string and tie it to the end of the spring and the hole on mass tying secure knots at both ends. Make sure the string goes around the pulley so that the pulley turns smoothly. The string should be tight, but not quite stretching the spring.
Spin the track to see how the mass moves out from where it started. Notice that if the track stops abruptly, the mass moves back to the center of the track.
Make sure to check the stop screws periodically to see if they have moved or become loose because of being hit by the mass.

Notes:

To put anything onto the track, line the square nut up with the grooves in the track and slide in.
Use a stable table, and make sure the base is level. Clamp down for best results.
The track scratches very easily, so be careful when tightening each component into place on the track.
Be gentle when spinning!

Demo Staff:

When putting the demo away, make sure to use the bags in the box for each part to prevent scratches.
Bags are labeled with what experiment uses each part, as well as what belongs inside.
This is a part of the Complete Rotational System from PASCO.

Last updated on July 31, 2026