Question

A light rod of length 1 m is pivoted at its centre and two masses of 5 kg and 2 kg are hung from the ends as shown in the figure. Find the initial angular acceleration of the rod assuming that it was horizontal in the beginning.

Answer 1

We know that, $T=I\alpha \Rightarrow 5g\times 0.5-2g\times 0.5=(5\times {0.5}^2+2\times {0.5}^2)\alpha \Rightarrow 3g=7\times 0.5\alpha \Rightarrow 30=7\times 0.5\alpha \therefore \alpha =\frac{60}{7}rad/s^2$