Question

A machine raises an object of weight 1500 N through a distance of 5m. What is its efficiency if the energy input is 15 000 J?

Answer 1

We have:

W = weight = 1500 N

D = distance = 5 m

Energy input = 15000 J

Apply:

Efficiency= useful output energy / input energy

Work = weight x distance = 1500 N x 5 m = 7500 J (useful output energy )

Efficiency = 7500 J / 15000 J = 0.5 or 50%