Question

"An ideal machine cannot be made practically." Justify the statement.

Answer 1

Ideal machine:

1. An ideal machine works on the principle, $\mathrm{Work}\mathrm{done}\left(input\right)=\mathrm{Work}\mathrm{done}\left(output\right)$.
2. The efficiency of the ideal machine is $100\%$.
3. But practically while using the machine, some part of the input energy is wasted in moving the parts of the machine and in overcoming the friction between the various parts of a machine.
4. Hence, an ideal machine cannot be made practically.