Question

You are to design a rotating cylindrical axle to lift 800 N buckets of cement from the ground to a rooftop 78.0 m above the ground. The buckets will be attached to a hook on the free end of a cable that wraps around the rim of the axle; as the axle turns, the buckets will rise. What should the radius of the axle be in order to raise the buckets at a steady 3.28 cm/s when it is turning at 7.24 rpm?

Answer 1

$$v=r\omega\\3.28=r\frac{7.24}{1}\frac{2\pi}{60}\\d=4.33\ cm$$