PIRA 1F20.10 Inertia of Rest: Inertia Balls
Photo Shows the Demonstration Used by the University
of Texas at Austin.

Instructions / Notes:
- A thin string is attached to a heavy steel ball, a metal bar/rod is attached to the
other end of the string so that you can pull on it.
- If you slowly lift the ball with the metal bar, the string should not
break.
- If you quickly jerk upward on the string, the string will break.
- Have the students guess where the string will break.
- Steel ball is about 6 cm in diameter and weighs about 1150 g.
Illustration is by Courtesy of the University of Minnesota.
Last Updated 2/17 - University of Texas at Austin Physics Dept.
- All Rights Reserved.