1.
In a certain weight lifting machine, a weight of 1 kN is lifted by an effort of 40 N. While the weight moves up by 100 mm, the point of application of effort moves by 5 m. Find the efficiency of the machine.
A
50%
B
40%
C
70%
D
60%
View Answer
Correct Answer: A — 50%
Explanation:
50%. Efficiency = Useful work output / Work input. Load = 1 kN = 1000 N, load displacement = 100 mm = 0.1 m, effort = 40 N, effort displacement = 5 m.