What is a Pulley?
It is a simple wooden or metallic machine that uses a wheel and rope to lift heavy loads. Nowadays, plastic pulleys are also available in the market to carry small loads.This can be rotated freely about an axis passing through its center. It can change the direction of a force which makes it much easier for people to lift up anything. With this, you can pull down on one end to lift the 10 kgs and one-meter high object.
It is classified into two types:
When the block of pulley is fixed on high platform, it is known as Fixed . An extensible string passes over the groove where its one end is attached to the body to be lifted while the other end is free.
When the block of pulley is not fixed but carries the load, it is known as Movable. An inextensible string is tied around the groove where its one end is fixed to a fixed support while the other end is kept free to apply the effort. As the effort is applied, the block together with the load moves upward.
The Velocity Ratio can be found by comparing the distance moved by effort and load.
Velocity Ratio (V.R) = Distance moved by the effort/Distance moved by the load