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An unruly demonstrator lifts a stone of mass 200 g from the ground and throws it at his opponent. At the time of projection, the stone is 150 cm above the ground and has a speed of 3.00 m/s. Calculate the work done by the demonstrator during the process. If it takes one second for the demonstrator to lift the stone and throw, what horsepower does he use?

Shane Macguire , 10 Years ago
Grade upto college level
anser 1 Answers
Aditi Chauhan

Last Activity: 10 Years ago

Sol. m = 200g = 0.2kg, h = 150cm = 1.5m, v = 3m/sec, t = 1 sec Total work done = ½ mv^2 + mgh = (1/2) × (0.2) ×9 + (0.2) × (9.8) × (1.5) = 3.84 J h.p. used = 3.84/746 = 5.14 * 10^-3

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