A uniform rod of length $0.90\ \text{m}$ is held horizontal and dropped from rest, without turning. After it has fallen $0.45\ \text{m}$, its left end strikes a fixed sharp edge and is caught there, so that the rod starts to turn about the edge, as shown in the figure. Take $g = 10\ \text{m/s}^2$. What is the angular speed of the rod just after the impact?

Fig. 1: The corner of a fixed block on the left. A horizontal uniform rod of length L = 0.90 m falls without turning, with its left end straight above the edge at height h = 0.45 m.