what is pulley for class 5

A pulley is a simple machine that uses a wheel and a rope to lift heavy loads. It is a wheel with a grooved rim that can hold a rope in place, and one end of the rope is attached to an object or a load of objects to be moved, while the other end of the rope is left free to be pulled on. When the free end of the rope is pulled, it lifts the weight on the opposite end of the rope. Pulleys can be used to reduce the time and energy taken to lift heavy objects. By adding more pulleys, you can increase your mechanical advantage and make it easier to lift the same load. However, as you increase the number of pulleys, you require a greater amount of rope to achieve the same result. There are two types of pulleys: fixed pulleys and movable pulleys. A fixed pulley is when the block of the pulley is fixed on a high platform, and an extensible string passes over the groove where one end is attached to the body to be lifted while the other end is free. A movable pulley is when the block of the pulley is not fixed but carries the load, and an inextensible string is tied around the groove where one end is fixed to a fixed support while the other end is kept free to apply the effort. Pulleys are used to gain mechanical advantage, especially for lifting weights.