A 1200 kg car traveling north at 14 m/s is rear-ended by a 2000 kg truck traveling at 30 m/s. What is the total momentum before and after the collision?

Total momentum before and after the collision = 76800 kgm/s along north.

Explanation:

Let positive x axis represent east and positive y axis represent north.

Momentum is conserved, that is total momentum before and after the collision are same.

A 1200 kg car traveling north at 14 m/s is rear-ended by a 2000 kg truck traveling at 30 m/s.

That is 1200 kg is moving north at 14 m/s and 2000 kg truck is also moving north at 30 m/s.

Momentum of car = 1200 x 14 j = 16800 j kgm/s

Momentum of truck = 2000 x 30 j = 60000 j kgm/s

Total initial momentum = 16800j + 60000j = 76800 j kgm/s

Total momentum before and after the collision = 76800 kgm/s along north.