A cricketer hits a ball from the ground level with a velocity $ \displaystyle \vec{v_0} = 20\hat{i}+10\hat{j}$ m/sec. Find the velocity of the ball at t = 1 sec, from the instant of projection (g = 10 m/sec^{2} ).

[ Ans: 20i^{^ }]

Solution : $\displaystyle \vec{v} = \vec{v_0} + \vec{a} t $

$\displaystyle \vec{v} = 20\hat{i} + 10\hat{j} – 10\hat{j} \times 1 $

$\displaystyle \vec{v} = 20\hat{i} $