13. Rotational Inertia & Energy

A small 10-kg object is connected to the right end of a thin rod of length 4 m and mass 5 kg. The rod is free to rotate about a fixed perpendicular axis on its left end, as shown below. The rod is initially held at rest, horizontally. When the rod is released, it falls, rotating about its axis, similar to a pendulum. What is the speed at the rod's center of mass when the rod is vertical? BONUS:What is object's speed when the rod is vertical?

In Example 11–1, the hand slowly pulls the string, causing the rotating mass (m = 0.75 kg) to gain speed.

(a) Calculate the work done by the hand.

In Example 11–1, the hand slowly pulls the string, causing the rotating mass (m = 0.75 kg) to gain speed

(b) Check that the work–energy theorem is satisfied.