Object AB is moving with the velocity of 1.23 m/s.
Givne data:
The mass of object A is m=3 kg.
The velocity of object A is u=2 m/s.
The mass of object B is M=10 kg
The velocity of object B is v=1 m/s.
Applying the conservation of momentum before and after the collision,
[tex]\begin{gathered} mu+Mv=(m+M)V \\ (3)(2)+(10)(1)=(3+10)V \\ V=1.23\text{ m/s} \end{gathered}[/tex]Thus, the object AB moving with a velocity of 1.23 m/s after the collision.