Mass of one of the objects, m1=100 g = 0.1 kg
Mass of the other object, m2=200 g = 0.2 kg
Velocity of m1 before collision, v1=2 ms−1
Velocity of m2 before collision, v2=1 ms−1
Velocity of m1 after collision, v3= 1.67 ms−1
Velocity of m2 after collision=v4
According to the law of conservation of momentum:
Total momentum before collision = Total momentum after collision
Therefore,m1v1+m2v2=m1v3+m2v4
2(0.1)+1(0.2)=1.67(0.1)+v4(0.2)
0.4=0.167+0.2v4
v4= 1.165 ms−1
Hence, the velocity of the second object becomes 1.165 ms−1after the collision.