Which of the following are in equilibrium? Choose all that apply. [NOTE: "spinning up" means the rate of spin is increasing. "spinning down" means the rate of spin is decreasing.] O A disc that is slowing down and is spinning down. O A baseball that has a constant velocity and has constant angular velocity. O A turntable that is at rest and is spinning up. O A tire that has a constant velocity and is spinning up. O A wheel that is slowing down and is not rotating. O A football that is slowing down and is spinning up. O A merry-go-round that is at rest and is not rotating. O A planet that moves along a perfectly circular orbit at a constant speed.

The rotating systems shown in the figure differ only in that the two identical movable masses are positioned a distance r from the axis of rotation (left), or a distance r/2 from the axis of rotation (right). If you release the hanging blocks simultaneously from rest, O A. the block at the right lands first. O B. both blocks land at the same time. O C. the block to the left lands first.

A wheel is rotating clockwise as shown (by the arrow). Its rotation axis coincides with the x-axis. A torque that causes the wheel to slow down is best represented by the vector 1 O 2 O 3 4 21 5

You stand on a turn-table with arms extended out horizontally, as shown in the figure below. In each hand, she holds an 8 kg weight. In this initial state, your professor and the turn-table are rotating at a constant rate of 9 rpm. Note that each weight is held 85 cm from the axis of rotation. Your professor brings her arms, and the weights, inwards towards her axis of rotation, as shown in the figure. What is the final rotational speed, in rpm, of your professor on the turn- table? You can assume that the weights are located on the axis of rotation in this final state. Wi Wt inital rinal State stüte The turn-table has a moment of inertia of 0.31 kg m^2. Your mated as a solid cylinder of uniform density with a mass of 65 kg and a radius of 16 cm. You can neglect the mass of the arms. assume that the weights can be approximated as point masses. body can be approxi-