A pendulum of length / = l m is released from ${\mathrm{\theta }}_0 = {60}^0$. The rate of change of speed of the bob at $\mathrm{\theta } = {30}^0$ is (g = 10 $\mathrm{m}/{\mathrm{s}}^2$)

• A

  $5\sqrt{3}$ $\mathrm{m}/{\mathrm{s}}^2$

• B

  5 $\mathrm{m}/{\mathrm{s}}^2$

• C

  10 $\mathrm{m}/{\mathrm{s}}^2$

• D

  2.5 $\mathrm{m}/{\mathrm{s}}^2$