Pulleys. Fixed Pulley: Wheel attached to surface Changes the direction of the applied force NO mechanical advantage – same amount of force is required. Movable Pulley : Pulley moves along the rope Wheel supports the load Effort is in the same direction as movement
In the second picture, the weight is held by two ropes instead of one. That means the weight is split equally between the two ropes, so each one holds only half the weight.
Pulleys are used to gain mechanical advantage trading the amount of rope you have to pull to lift an object for how heavy the object can be.
The more lines of support (ropes) a pulley has, the more mechanical advantage it has!