Question
Physics Question on laws of motion
250 N force is required to raise 75 kg mass from a pulley. If rope is pulled 12 m then the load is lifted to 3m, the efficiency of pulley system will be
A
25%
B
33.30%
C
75%
D
90%
Answer
75%
Explanation
Solution
The correct option is(B): 75% η =usefulwork/total work=mgh/fxd(75)x3/250x12=0.75