Question

1. The angular velocity of a rotating wheel increases by 1.6rev/s every minute. The angular acceleration in rad/s^2 of this wheel is: 
2. A Ping-Pong ball is shot into a circular tube that is lying flat (horizontal) on a tabletop. When the Ping-Pong ball exits the tube, which path will it follow in Figure below?
3. A crane has an arm length of 8.1 m inclined at 30^o with the vertical. It carries a container of mass of 2.6 kg suspended from the top end of the arm. Find the magnitude of the torque produced by the gravitational force on the container about the point where the arm is fixed to the crane. (Neglect the weight of the arm)

Answer 1

1. $\alpha=\Delta \omega/t=0.027\text{ rad/s}^2.$

2. The ping-pong ball will travel along a straight line.

3. The torque is

$$T=mgL\sin(90°-\theta)=179\text{ N}·\text m.$$