Given,
The momentum of object A before the collision, p₁=10 Ns
The momentum of object B before the collision, p₂=3 Ns
The momentum of object A after the collision, p₃=5 Ns
From the law of conservation of momentum, the total momentum of a system always remains constant. Thus the total momentum of the objects before the collision must be equal to the total momentum of the objects after the collision.
Thus,
![p_1+p_2=p_3+p_4](https://img.qammunity.org/2023/formulas/physics/college/u5mihimvwoxr8bmg01anypq54dmwy88xb2.png)
Where p₄ is the momentum of object B after the collision.
On substituting the known values,
![\begin{gathered} 10+3=5+p_4 \\ \Rightarrow p_4=10+3-5 \\ =8\text{ Ns} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/mrsrjdnwgzwpfacbka5x5jrz2buvxuppxe.png)
Thus the momentum of the object B after the collision is 8 Ns