Question:
An unruly demonstrator lifts a stone of mass $200 \mathrm{~g}$ from the ground and throws it at his opponent. At the time of projection, the stone is $150 \mathrm{~cm}$ above the ground and has a speed of $3.00 \mathrm{~m} / \mathrm{s}$. 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?
Solution:
