A small particleof mass m is projected at an angle $\theta$ with the x-axis with a initial velocity $v_0$ in the x-yplane as shown in the figure. At a time $t < \frac{v_0 \sin \theta}{g}$, the angular momentum of the particle is <br> <br> where $\hat{i}, \hat{j}$ and $\hat{k}$ are unit vectors along $x, \; y$ and $z-axis$ respectively.

Question

( A ) $mgv_0t \cos \theta \hat{k}$
( B ) $-\frac{1}{2} mgv_0t^2 \cos \theta \hat{k}$
( C ) $- mgv_0t^2 \cos \theta \hat{j}$
( D ) $\frac{1}{2} mgv_0t^2 \cos \theta \hat{i}$