Inertia Block (1F20.10)

Description:

A heavy block is suspended between two loops of string. A slow and steady pull on the bottom loop will break the upper string, while a quick jerk will break only the lower string (due to the high inertia of the mass).

Procedure or Operation Notes:

Pull fast to break the bottom loop. Pull slowly to break the top loop. Note that string (and knots) can vary in strength and might not break as described.

The top loop of string should be a little longer than the bottom loop so that the wide part of the connecting rod sits below the horizontal support beam.

References, Comments, or Footnotes:

1) This was originally called the Inertia Ball because it was done with a heavy suspended bowling ball.