Answer:
The correct answer is
p = p₁ + p₂
Step-by-step explanation:
Newton's second law states that force = the change of momentum produced therefore since the collision is inelstic then the change of momentum of each car is p₁ and p₂ and the force of the collition is proportional to p₁ + p₂ that is
F ∝ p₁ + p₂ and since force is directly proportional to p we have
p = p₁ + p₂