Question

What is an ideal machine? Is such a machine present in the world? If No justify your answer!

Answer 1

Hey there!

What is Efficiency?
↪The ratio between the output work to the input work done on the machine is called efficiency of the machine.

There's no machine whose efficiency is 100%. If it happens, this machine will be called as Ideal Machine.

The machine cannot have its efficiency 100% because -:
↪The moving parts of the machine are not frictionless
↪The string is not perfectly elastic
↪The different parts of machine are not perfectly rigid

;-)