Three particles A, B and C of equal mass move with equal speed 10 m/sec along the medians of an equilateral triangle as shown in the figure. They collide at the centroid G of the triangle. After the collision, A comes to rest, B retraces its path with the speed 10 m/sec. The velocity of C is _______ m/sec.

Answer

10

Explanation

Just before collision net linear momentum of the system is zero. As no external force is acting on the system, the linear momentum just after collision should also be zero. It is given A comes to rest. Therefore, B and C should have equal and opposite linear momentum. As masses of B and C are equal hence the velocity of C should be V in opposite direction of velocity of B.