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A bucket of water 50 kg is raised from a depth of 100m to the ground by a rope. The mass of the rope is 1 kg per meter. What is work done. |
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Answer» It can be DONE in two ways. Given BUCKET of water = 50 kg, depth = 10 m, mass = 1 kg/ m Weight of bucket = 50 x 9.8 x 10 (work done in lifting) = 4900 J Mass of rope 10 x 1 kg = 10 kg and wt of rope = 10 x 9.8 = 98 N Work done in raising the bucket = 98 x 10 = 980 J Total work done = 4900 + 980 = 5880 J OR Mass = 1 x L kg Since depth of well is 10 m L = 10 m So mass = 1 x 10 = 10 kg Mass of water raised M = 50 kg Work done in raising + bucket filled water W = (mass of rope + mass of water raised) x g x height W = (10 + 50)(9.8)(10) W = 5880 J |
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