PURPOSE: To show that a larger impulse is imparted by an elastic collision.

DESCRIPTION: A vacuum mud ball at the end of a rod is held horizontally and released so that it swings into a wooden block. The vacuum mud ball is replaced by a superball with the same mass, and the experiment repeated. Q: In which of these cases will the wood block be knocked over? A: The superball knocks over the wooden block because it bounces back, imparting more momentum to the block.

Click your mouse here for vacuum mud ball collision or for superball collision.

SUGGESTIONS: Use a balance to show that the masses are equal.

See Question of the Week #77 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA 1N30.50)

EQUIPMENT: Superball, vacuum mud, 1200 gram wood block, balance, physical pendulum mechanism with clip retainer.

SETUP TIME: 5 min.