You are helping to design a new fire escape for your third-floor apartment. You step out the window onto a crossbar that is attached to a rope, which in turn is wound around a massive solid cylindrical flywheel that can turn on its axis.
As you fall at increasing speed, the rope causes the flywheel to turn at increasing angular velocity. Your task is to
choose a flywheel that will enable you to move at a safe 2.0 m/s when you reach 10 m below your starting position.
Your mass is 80 kg. Determine the rotational inertia and mass of the uniform 0.80 m radius flywheel you need to
buy.

The correct answer to the question is efficiency i.e the ratio of output work to the input expressed as percent is called the efficiency of a machine.

EXPLANATION:

The efficiency of a machine gives the idea about the amount of energy conserved or lost in a process.

Let us consider a machine which is subjected to some amount of work done on it.

Let the work done on machine or the effort  is W.

The machine performs its work due to the effort and produces the desired output.

Let the output produced by the machine is W' .

Hence, the efficiency of the machine is calculated as -

                        Efficiency