Pulleys

A pulley is also a type of force transformer. It consists of one or more grooved sheaves. The sheave rotates freely around its axle. A rope or a steel cable runs through the sheave groove. For our purposes we are assuming that the sheave rotates without any frictional losses.

The illustration provided here shows the basic operation of a pulley. At the top the pulley is supported by a hook and tackle arrangement. A rope is slung over the pulley. A weight is attached to the rope on the left hand side of the pulley. Before you do anything, under initial conditons, the weight is supported at the bottom as shown.

On the right hand side, the rope hangs freely. We can pull on the right hand side rope to lift the weight. Click on the “Apply Force” button. This illustrates what happens when we pull down on the rope on the right hand side. Notice that the weight rises.