Assignment:
Question 1. A playground whirl consists of a uniform disk of mass 10M and radius R. It is spinning at a rate of 2.0 rmp. A child mass M, originally at rest, steps on to the whirl. She does not slide back off.
- What is the final angular velocity of the whirl and the child (assuming the axis is frictionless)?
- What fraction of the initial kinetic energy is lost? Where did it go?
Question 2. The whirl is problem 2 is now connected to a motor that keeps it rotating at a constant 20.0 rpm even with the child aboard. She is initially at the center. After awhile she begins walking from the center. Draw a free body diagram of the child when she is a distance r from the center. If the coefficient of friction is 0.25, how far can she walk from the center before sliding off. How fast is she going at the maximum distance?