Pulley - Mechanical Advantage

Purpose

To demonstrate quantitatively the mechanical advantage of a pulley.

Equipment

Pulley system mounted as photographed in rolling frame, six 1 kg weights, small balancing weights.

Images

b3-12

Description

The system is initially balanced to account for the weight of the pulleys and rope by adding small weights on the free end of the rope. For every two kilograms hanging from the pulley, the system requires one kilogram hanging from the free end of the rope to obtain equilibrium. Show that deviation from the 2:1 ratio destroys the static equilibrium.

References

Albert A,. Bartlett, What is (or was) White's Pulley?, TPT 14, 13, (1976). Letter to the Editor: Mario Iona, More on White's Pulley, TPT 13, 260 (1976).