Question

How is the mechanical efficiency of a machine usually expressed?

Group of answer choices

as a fraction

as a percentage

as inches or feet

as one of three classes

Answer 1

As a percentage

Step-by-step explanation:

The mechanical efficiency of a machine is the percentage of energy in input to the machine that is converted into useful work.

Mathematically, the efficiency of a machine is given by:

`\eta=(W)/(E)\cdot 100`

where:

W is the useful work in output from the machine

E is the energy in input to the machine

For example, a machine with 80% efficiency means that it converts 80% of the input energy into work.

A machine can never be 100% efficient, since part of the input energy is wasted due to the presence of frictional forces.

So, the efficiency of a machine is expressed as a percentage.