Question

efficiency is the ratio of work input to work output. it is represented as a percentage (%). the higher the percentage (%), the higher the efficiency of the machine. work input is the amount of work put into a machine. work output is the amount of work done by the machine. friction is the resistance force one object exerts on another when they touch. choose the correct answer what do we call the ratio of work input to work output for a machine? work output efficiency friction

Explanation:

The question is about a concept in physics (a subfield of Natural Science) related to machines. From the left panel, we know that efficiency is the ratio of work input to work output (expressed as a percentage). Work output is the work done by the machine, and friction is a force that opposes motion. So the ratio of work input to work output for a machine is called efficiency.

Answer:

B. Efficiency (assuming the options are labeled with "Work output", "Efficiency", "Friction" and "Efficiency" is the correct one; if the options are in order as shown, the middle option which is "Efficiency")