Question

An automobile engine is 15 percent efficient. How many joules of input work are required to produce 15,000 joules of output work to move the car?

Answer 1

15,000J/.15% = 100,000 J

If you want to check,
Multiply 100,000 by .15 and you get 15,000 J

Answer 2

Answer:100,000Joules

Explanation:

Efficiency of machines is the ratio of work done by machine (work output) to the work put in the machine (work input)

Efficiency = Work output/Work input

Given efficiency = 15%

Work output = 15,000Joules

Work Input = ?

Substituting in the formula of efficiency

15% = 15,000/Work Input

15/100 = 15,000/Work Input

15× Work input = 15,000×100

15 × Work input = 1,500,000

Work input = 1,500,000/15

Work input = 100,000Joules