Given
Mass of one object, m=4 kg
Velocity of the object, u=29 m/s towards the right
Mass of the other object, m'=11.5 kg
Velocity of the other object, u'=18 m/s towards left
After collision
The object with mass 11.5 kg moves at a speed, v'=4 m/s towards right
To find
The velocity of the object with mass 4 kg after collision
Step-by-step explanation
Let the direction towards right be positive
By conservation of momentum
![\begin{gathered} mu+m^(\prime)u^(\prime)=mv+m^(\prime)v^(\prime) \\ \Rightarrow4*29-11.5*18=4v+11.5*4 \\ \Rightarrow v=-34.25\text{ m/s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/gbx3mufq8har9t7d4jwmnv1a2yk9t0nr4x.png)
Conclusion
The velocity of the object is C.-34.25 m/s