Why, in a real machine, is the output work always less than the input work?

2 Answers

All machines have losses.If it is moving there are friction between parts.If it is rotating it have to over come air resistance.If it is a heat engine we can not extract all heat some is lost to atmosphere..

Explanation:

Different losses are reason for less efficiency.

Jun 5, 2016

The transfer of energy is usually not 100% efficient.

Explanation:

In a real machine, energy loss may be contributed to heat or sound energy. However, the limits do not stop there as electrical energy can also be transformed into other forms of energy.