Answer:
As a percentage
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:
[tex]\eta=\frac{W}{E}\cdot 100[/tex]
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.
