Question

A man lifts various loads with the same lever. The distance of the applied force from the fulcrum is 2.00 m and the distance from the fulcrum to the load is 0.500 m. A graph of resistance force vs. effort force is shown. What is the mechanical advantage of the lever? What is the ideal mechanical advantage of the lever? What is the efficiency of the lever? Show your work.

Answer 1

The actual mechanical advantage is just the slope of the line in the graph.

The ideal mechanical advantage is found from the balance of torque about the fulcrum. \[-F_a 2 = F_L 0.5\]Since mechanical advantage is defined as\[{F_L \over F_a}\], the ideal mechanical advantage of the system is 4.

The efficiency is defined as\[\eta = {\rm ideal \over actual}\]