A rope and pulley system is a simple machine made by connecting a rope to one or more pulleys. You apply the input force to the rope and the output force is exerted on the load you are lifting. One person could easily lift an elephant with a properly designed system of pulleys.

The mechanical advantage of a pulley system depends on the number of strands of rope directly supporting the load. To make a rope and pulley system with a greater mechanical advantage, you can increase the number of strands directly supporting the load by taking more turns around the pulleys.