Two particles are kept on a smooth surface move towards

Two particles are kept on a smooth surface move towards
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Two particles are kept on a smooth surface, move towards each other due to mutual attraction. If the position and velocities of  the particles at t=0 is as shown in the figure. Then position of the center of mass at t=2 sec is

A.

x=7 m

B.

x=5 m

C.

x=3 m

D.

x=2 m

Please scroll down to see the correct answer and solution guide.

Right Answer is: A

SOLUTION

Initial position of centre of mass
  xCM=m1x1+m2x2m1+m2
xCM=1×0+1×102=5 m
Velocity of centre of mass
vCM=m1v1+m2v2m1+m2

vCM=1×51×32=1 m/s 

Displacement of  CM in 2 sec=vCM×t=2 m

So location of CM =5+2=7 m