Question 12
Simple MachinesA machine is used to lift a load of 20 N through a height of 10 m. If the efficiency of the machine is 40%, how much work is done?
- A.300 J
- B.120 J
- C.80 J
- D.500 J
Show the answer and explanation
Answer: D (500 J)
Explanation
Useful work output = 20 × 10 = 200 J. Work put in = output ÷ efficiency = 200 ÷ 0.4 = 500 J.