Q: A ball falling with velocity $\vec{v_i} = -0.65 \hat{i} – 0.35 \hat{j} m/s$ is subjected to a net impulse $\vec{I} = (0.6 \hat{i} + 0.18 \hat{j}) Ns $ . If the ball has a mass of 0.275 kg , calculate its velocity immediately the impulse .
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Sol: $\vec{I} = m \vec{v_f} – m \vec{v_i}$
$\large m \vec{v_f} = m \vec{v_i} + \vec{I} $
$\large \vec{v_f} = \vec{v_i} + \frac{\vec{I}}{m} $
$\large \vec{v_f} = -0.65 \hat{i} – 0.35 \hat{j} + \frac{\vec{(0.6 \hat{i} + 0.18 \hat{j})}}{0.275} $
$\large \vec{v_f} = 1.53 \hat{i} + 0.305 \hat{j} m/s$