Question

A forklift raises a box above the floor and does 2,000 J of work. If the forklift motor consumes 3,000 J of electrical energy from the battery to raise the box, what is the efficiency of the lift?

Answer 1

Efficiency = (useful output energy) / (input energy)

Efficiency = (2,000 J) / (3,000 J)

Efficiency = 2/3

or

Efficiency = 66.7%

Answer 2

Efficency=useful energy output/total energy input x 100. 2000/3000 x 100 = 66.7%