As the block is exploded only because of its internal energy, the net external force on the system is zero.
Thus, the centre of mass of does not change.
Let the body was at the origin of the co-ordinate system during explosion.
Resultant velocity of two bodies of equal mass moving at a speed of 10 m/s in + x-axis and + y-axis direction, is given as:
If the centre of mass is at rest, the third part having equal mass as that of the other two masses will move in the opposite direction (i.e. w.r.t. +x-axis) at the same velocity of .