The pulleys

A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt.

Pulley is a fixed wheel with a rope string passing through a groove in its rim.

An effort is applied at one end to overcome a load at another end.

For a pulley

The  velocity ratio of pulley system is equal to the  number of string supporting the load

V.R = n where n is the number of string supporting the load.

Read more about PHYSICS for High Schools