Q 11-04-019NEETJEE MainEAMCET 2009 (Engineering)Medium
A particle of mass $4m$ at rest explodes into three pieces of masses $m$, $m$ and $2m$. The equal masses move along the $X$-axis and $Y$-axis with velocities $4\ \text{m s}^{-1}$ and $6\ \text{m s}^{-1}$ respectively. The magnitude of the velocity of the heavier mass is
Answer: (B) $\sqrt{13}\ \text{m s}^{-1}$
Initial momentum is zero, so the heavier piece carries momentum equal and opposite to the sum of the other two:
$$2m\,v_3 = \sqrt{(4m)^2 + (6m)^2} = m\sqrt{52} = 2\sqrt{13}\,m$$
$$v_3 = \sqrt{13}\ \text{m s}^{-1}$$
Solution by Sreeraj P, M.Sc Physics