In a simple machine the energy input is 120J. If the efficiency of the machine is 80%, calculate the energy output of the machine.

120 * 0.80 = ____

To calculate the energy output of the machine, we need to apply the concept of efficiency. Efficiency is defined as the ratio of useful output energy to the input energy. In this case, the efficiency is given as 80%, which can also be expressed as 0.80.

The formula for efficiency is:

Efficiency = (Useful output energy / Input energy) * 100

We can rearrange this formula to solve for the useful output energy:

Useful output energy = (Efficiency / 100) * Input energy

Substituting the given values:

Efficiency = 0.80
Input energy = 120J

Useful output energy = (0.80 / 100) * 120J

Calculating the useful output energy:

Useful output energy = 0.80 * 120J

Useful output energy = 96J

Therefore, the energy output of the machine is 96J.