• # question_answer A uniform rod AB of mass m and length la is falling freely without rotation under gravity with AB horizontal. Suddenly the end A is fixed when the speed of the rod is v. The angular speed with which the rod begins to rotate is A) $\frac{v}{2a}$                                  B)  $\frac{4v}{3a}$C) $\frac{v}{3a}$                                  D)  $\frac{3v}{4a}$

Angular momentum about A will be conserved, i.e., ${{L}_{i}}={{L}_{f}}$ $mva=I\omega$or $mva=\frac{m{{(2a)}^{2}}}{3}\omega$$\therefore$$\omega =\frac{3v}{4a}$ Hence, the correction option is [d].