Centre Of Mass

As initially both the particles were at rest therefore velocity of centre of mass was zero and there is no external force on the system so speed of centre of mass remains constant i.e., it should be equal to zero.

Let masses are kept at points and where denotes the center of mass of the system which lies at a distance from point .
Using


Thus the center of mass of the system lies at distance of unit away from point om the line joining the masses i.e line
Hence the center of mass of the system lies at

Step 1: Centre of mass: xcm = (1+2+3)/(3) = 2, ycm = (1+2+3)/(3) = 2

The correct option is (B): 10 m/sec.
Then the man is moving wrt the ice in the opposite direction at (30-V) velocity. Recoil velocity V = 10 m/s in the opposite direction of movement of the man.
100 * (30-V) - 200 * V = 0
300 V = 3000
Velocity of the man wrt to ice = 20m/s
(Their relative velocity = 30 m/s)

Answer (d)