Two cars collide inelastically and stick together after the collision. Before the collision, the magnitudes of their momenta are p1 and p2. After the collision, the magnitude of their combined momentum is p. Of what can one be certain?

The correct answer is

p = p₁ + p₂

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

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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