PURPOSE: To illustrate mechanical advantage.

DESCRIPTION: The screw jack is used to lift the back end of the wagon with several people aboard. It can easily be operated with one hand, because it has a mechanical advantage of about 420 when used with a 22 inch handle. A shorter handle can easily lift one or two people.

SUGGESTIONS:

REFERENCES: (PIRA unknown.)

EQUIPMENT: Screw jack, wood block, and wagon, as photographed.

SETUP TIME: 5 min.