a motor pump of 400 w operates for 2 minutes and 40 secs and in doing so raises 200kg of water to the top of a building. cal the height of the building.

Dear Student,

Power, P=400 Watttime, t=2 min 40 sec=2×60+40 secondst=120+40=160 smass, m=200 kgPower=work donetimework done, W=P×tW=400×160=64000 JAlso, W=Fsor, W=mgs  ...(1)where, Force, F=mgm=massg=acceleration due to gravity=9.8 m/s2s=displacementfrom equation (1),64000=200×9.8×ss=64000200×9.8=32.65 m

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As we know that power= work done/ time Then, work done= power × time =400w× 160sec = 64000 j Work done = force×displacement = mass × acceleration × displacement 64000 = 200kg×10m/s× d d = 200kg×10m/s/64000 d = 1/32m
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