Read about short note on pulley. Here given importance of pulley for education.
घिरनी का महत्व व प्रयोग की जानकारी अंग्रेजी मे दी जा रही हैं।
A pulley is a grooved wheel with a rope or chin around it. It can be fixed to a support or can be movable. It is a simple machine that makes work easy by changing the direaction of the force applied.This means instead of pulling the load upwards,you are now pulling the rope downwards.
The most common use of a pulley is to draw water from a well. The pulley is fixed to a support with a rope over it. The pot of water attached to one end of the rope is pulled upward by pulling the other end of the rope downward.Remember that it is easier to pull down than to pull up.That is why pulley helps to fetch water easily. However, a pulley does not reduce the effort required to lift a heavy load.It only changes the direction of force applied. Flags are hoisted on a flagpole with the help of pulley.
When more than one pulley is attached to the same rope around them,lifting or lowering of loads become easier with very less effort. A crane works on many pulleys and thus is able to shift extremely heavy loads.
