Question

Suppose we have a small ball, conected by a weightless rigid bar to a rotating point, around which it can easily rotate because of gravity. We hold it vertically and give it a little shake, so that it begins the motion. What is the angle which the bar will form with the initial direction when the vertical component of its speed is maximal?

Answer 1

In this case $v_{ver}=\sin\alpha\cdot\sqrt{2Rg(1-\cos\alpha)}$

The vertical component is maximal when $\alpha=90°$.