Question

Suppose you observe your friend (mass 67.2 kg) stand at the very edge of a motionless merry-go-round (modelled as a thin disk with moment of inertia 6.1 kg m 2). At some point, your friend walks around and along the edge at a speed 1.5 m/s perfectly tangent to the edge at all times, relative to the merry-go-round’s surface. Take the radius of the merry-go-round to be 1.2 m.

(a) Calculate the speed (in m/s) of your friend relative to the stationary ground.

(b) Calculate the speed (in m/s) of your friend relative to the stationary ground if the merry-go-round becomes massless.

(c) Calculate the speed (in m/s) of your friend relative to the stationary ground if the merry-go-round becomes arbitrarily (infinitely) massive.

Answer 1