What is force advantage?

Answer 1

Force advantage (mechanical advantage) is the ratio of the load to the effort.

An example of a simple first class lever, one in which the sequence is effort-fulcrum-load, is the prying of a rock out of the ground with a pole. Supposing the pole is 11 feet long and we wedge one end of it under a 100 Ib rock with a smaller rock as a fulcrum. The distance along the pole between where we apply effort and the fulcrum is exactly 10 feet. If we push down on the pole with 10 Ib of force, then because of the leverage of this machine we will actually exert 100 Ib of upward force at the base of the rock. A moment of force is developed which is the product of the force effort and the shortest distance between the line of action of the force and the axis of rotation, the effort arm. . In the example above the force advantage of this first class lever is 10: for a force of 1 Ib applied we lifted 10 Ib of rock.