A pulley system holding a rope that is pulled out a distance of 20 m is used for lifting a 2500 kg grand piano. The piano can be raised 3 m by application of a 375 N force to the rope
What will be an ideal response?
The weight of the piano is 2500 kg x 10 m/s2 = 25,000 N. To lift the piano 3 m,
an amount of work 25,000 N x 3 m = 75,000 J must be done. The maximum amount of
work that can be done by the 375 N force raised through 20 m is 375 N x 20 m = 7,500 J.
This is far too little to do the work to raise the piano.
The piano can only be made to raise at most by 0.3 m, because 25,000 N x 0.3 m = 7,500
J.
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