Question

A machine of efficiency 80% does 3000j of work. caculate the energy used in over function?​

Answer 1

The machine does 3000 J of work.

This is 80% of the energy that was put into the machine.

3000 J = 0.80 x (Input energy)

Divide both sides of the equation by 0.80 .

Input energy = 3000 J / 0.8

Input energy = 3750 J