A particle of mass 4 m explodes into three pieces of masses $m, m$ and $2m$. The equal masses move along X and Y axes with velocities $4 ms^{-1}$ and $6\;ms^{-1}$ respectively. The magnitude of the velocity of the heavier mass is :

Question

$$\begin {array} {1 1} (1)\;\sqrt {17}\; ms^{-1} & \quad (2)\;2 \sqrt {13} ms^{-1} \\ (3)\;\sqrt {13}ms^{-1} & \quad (4)\;\frac{\sqrt {13}}{2} \end {array}$$