Question

efficiency is a comparison of how much work goes into a machine versus how much work comes out of a machine. how is efficiency expressed? in kilograms as a percentage (%)

Explanation:

Efficiency is calculated as the ratio of useful output work to input work. To express this ratio in a more intuitive and standardized way, it is commonly multiplied by 100 and presented as a percentage. This percentage value gives a clear indication of how effectively a machine converts input work into useful output work. For example, if a machine has an efficiency of 60%, it means that 60% of the input work is converted into useful output work, while the remaining 40% is lost (e.g., as heat due to friction). Kilograms is a unit of mass and has no relation to the concept of efficiency (which is a dimensionless ratio when expressed as a percentage).

Answer:

as a percentage (%)