Question

Why is a machine not 100% efficient?

• A. Different parts of the machine are not smooth and rigid
• B. String in it (if any) is not perfectly elastic
• C. Moving parts are not weightless
• D. All of the above

Answer 1

The correct option is D

All of the above

A machine is not 100% efficient as a huge amount of energy is wasted in form of frictional losses because its moving parts are not weightless, the string in it (if any) is not perfectly elastic and the different parts of a machine are not perfectly rigid and also not perfectly smooth. The frictional losses are further converted into heat and sound energy.