Explanation:
It is given that,
Mass of a box car, [tex]m_1=14000\ kg[/tex]
Initial speed of a box car, [tex]u_1=1.5\ m/s[/tex]
Initial speed of another stationary car is 0 as it was stationary
Mass of another box car is 10,000 kg
Let V is the speed of the cars just after the collision. It is based on the concept of inelastic collision. So, using the conservation of linear momentum we get :
[tex]m_1u_1+m_2u_2=(m_1+m_2)V\\\\m_1u_1=(m_1+m_2)V\\\\V=\dfrac{m_1u_1}{(m_1+m_2)}\\\\V=\dfrac{14000\times 1.5}{(14000+10000)}\\\\V=0.875\ m/s[/tex]
So, the speed of the cars just after the collision is 0.875 m/s.