Answer:
Explanation:
Given
Both cars mass is m
and solving problem in Vertical and horizontal direction
considering + y and +x to be positive and u be the final velocity of system
Conserving Momentum in Vertical direction

------1
Conserving momentum in x direction
-----2
squaring and adding 1 &2




Answer:
im not too sure about that all i know is history
Mass is measured in kg
Velocity is measured in ms^-1
Hope this is what you were looking for