Assignment:
1. A skater spins on the ice with the arms stretched out and she is making one rotation per second, ω1 = 6.28 rad/s. Then she pulls arms toward the body. Consider that the arms have effective mass m, and the distance of the effective mass from the axis of rotation initially was r1 = 0.5 m. Then when the arms are pulled back, the distance of the effective mass from the axis of rotation became r2 = 0.2 m.
Calculate the angular velocity of the skater ω2, when she pulls her arms. Is it faster or slower then initial rotation?
2. A bicycle is moving with linear velocity v = 5 m/s. Each bicycle wheel has the mass m = 5 kg. Consider that the mass of the wheel is istributed in the rim. The bicycle has two identical wheels, and the frame of the bicycle has the mass M = 10 kg.
Calculate the total kinetic energy of the bicycle.