Answer:
p = 0.16 kgm/s
Step-by-step explanation:
the initial momentum combined of the two cars and the final momentum of the paired cares are the same, so we just need to find the initial momentum
p = m1v1 + m2v2
p = 0.04*4 + 0.04*0
p = 0.04*4
p = 0.16 kgm/s