A machine requires an effort of 800 N to lift a mass of 300 kg. How would you calculate the efficiency of the machine?

To calculate the efficiency of a machine, the appropriate formula takes into account both the load being moved and the effort exerted to move it, as well as the distances that each moves. The correct formula for efficiency is:

Efficiency = (Load x Distance moved by Load) / (Effort x Distance moved by Effort).

This formula reflects how effectively the machine converts the input work (effort over a distance) into useful output work (load over a distance). The load represents the weight being lifted, and the effort is the force applied to lift that load. By incorporating the distances over which both the load and effort are moved, this equation provides a more comprehensive measure of the machine's performance than just comparing force to force.

In comparison, other potential formulas do not incorporate the distances moved, which is critical in providing a complete understanding of efficiency. This ensures that the efficiency calculation is accurate and meaningful, indicating how much of the work input goes into doing work on the load. For machines that operate with varying distances, relying solely on load and effort without incorporating distance would yield misleading efficiency values.