Question

Why is the efficiency of a machine always less than 100 percent? The work input is too small. It cannot have an IMA greater than 1. Some work input is lost to friction. The work output is too great.

Answer 1

Some work input is lost to friction

Answer 2

Some work input is lost to friction

Step-by-step explanation:

The efficiency of a machine is defined as:

`\eta = (W_(out))/(W_(in))` (1)

where

`W_(out)` is the work output

`W_(in)` is the work input

Due to the law of conservation of energy, the work output can never be larger than the work input (because energy cannot be created). Moreover, in real machines part of the work input is lost due to the presence of frictions: as a result, part of the energy in input is converted into thermal energy or other forms of energy, and so the work output is smaller than the work input, and so the ratio (1) becomes less than 1, and so the efficiency is less than 100%.