by Ashton and Jordan
Pullys are one of the six simple machines. Pulleys such as cranes are often used in construction work to lift heavey loads.The rope of cable pulls on one side of the rope to make wheel turn. Pulleys can be attached to helicopters to carry things . Pulleys work by changing the direction of force it makes it easier to lift a load.
Two pulleys make it easier it decreases the effort to move the load. Each rope holds some of the load. When you have two pulleys the load feels lighter. Two pulleys can lift a bigger load. Moveable pulleys decreases the effort to move a large load.