Q 11-05-020NEETEAMCET 2013 (Medical)Medium
A ball of mass $m$ moving with a horizontal velocity $v$ strikes the bob of mass $m$ of a pendulum at rest. During this collision, the ball sticks with the bob of the pendulum. The height to which the combined mass rises is ($g$ = acceleration due to gravity)
Answer: (B) $\dfrac{v^2}{8g}$
Concept. Momentum in the collision, then energy in the swing.
Step 1. Common speed. $V = \dfrac v2$.
Step 2. Height. $\dfrac{V^2}{2g} = \dfrac{v^2}{8g}$.
Answer. $\dfrac{v^2}{8g}$ (Option B).
Solution by Sreeraj P, M.Sc Physics