Their speed is 5 m/s.
c. 5 m/s
Step-by-step explanation:
The situation described in the given problem is an example of inelastic collision where the objects stick together and the kinetic energy won’t be conserved. Some of the kinetic energy might transform to thermal energy or some other form of energy.
Here the mass of first vehicle
mass of second vehicle

velocity of the first vehicle
velocity of the second vehicle
Since the masses of the vehicles are combined after the collision their velocities also will be combines.
Therefore mass of the system after collision =

velocity of the system after collision = v
According to the law of conservation of momentum



