Answer
A pulley allows one to change direction of force.
For example, one can lift a heavy box up by attaching it with a rope over a pulley. A more complex systems of pulleys can however reduce the force applied in order to lift the object. An inclined plane can also be used to reduce the force. In pushing a heavy box up as inclined plane, the force required is less than the box's weight.
Work Step by Step
A pulley allows one to change direction of force.
For example, one can lift a heavy box up by attaching it with a rope over a pulley. A more complex systems of pulleys can however reduce the force applied in order to lift the object. An inclined plane can also be used to reduce the force. In pushing a heavy box up as inclined plane, the force required is less than the box's weight.
