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250 N force is required to raise 75 kg mass from a pulley. If the rope is pulled 12 m, then the load is lifted 3 m. The efficiency of the pulley system will be
(3) 75%
Taking g = 10 m/s2:
Output work (useful) = mgh = 75 10 3 = 2250 J
Input work = F d = 250 12 = 3000 J
= 22503000 100
= 75\%
Answer: (3)
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