This free interactive 3D physics simulation demonstrates how pulley systems help lift heavy objects. Students can explore fixed pulleys, movable pulleys, and compound pulley systems while observing the relationship between input force, weight, efficiency, and mechanical advantage.
A pulley system can reduce the input force needed to lift an object by distributing the load across multiple supporting rope segments. The more supporting rope segments a system has, the greater the ideal mechanical advantage.
In an ideal pulley system, the mechanical advantage is approximately equal to the number of rope segments supporting the load.
Real pulley systems are not perfectly efficient because of friction, pulley weight, and energy loss. When efficiency is less than 100%, the input force must be larger than the ideal value.
A fixed pulley changes the direction of the applied force, but it does not reduce the required input force in an ideal system.
A movable pulley reduces the input force because the load is supported by more than one rope segment.
A compound pulley system combines fixed and movable pulleys to increase mechanical advantage and make lifting easier.
Lower efficiency means more input force is required because some energy is lost to friction and pulley motion.
A pulley is a simple machine made of a wheel and a rope or cable. It helps lift objects by changing the direction of force and, in some systems, reducing the input force needed.
No. A single fixed pulley mainly changes the direction of the force. In an ideal case, the input force is approximately equal to the weight being lifted.
A movable pulley allows more than one rope segment to support the load, so each segment carries only part of the weight.
A pulley system reduces input force by increasing the distance over which the force is applied. This follows conservation of energy: less force requires more distance.