Question

Two cars collide at an intersection. One car has a mass of 800 kg and is

moving 15 m/s to the north, while the other has a mass of 900 kg and is
moving 18 m/s to the south. What is their combined momentum?
OA. 4200 kg.m/s south
OB. 28,200 kg-m/s south
OC. 28,200 kg-m/s north
OD. 4200 kg-m/s north

Answer 1

Answer: option D: 4200 kg-m/s north.

Explanation: The energy of the primary car moving north is:

p1 = m1 * v1 = 800 kg * 15 m/s = 12,000 kg·m/s north

The force of the moment car moving south is:

p2 = m2 * v2 = 900 kg * (-18 m/s) = -16,200 kg·m/s north

Note that the energy of the moment car is negative because it is moving within the inverse heading to the positive course we have chosen.

To discover the combined force, we include the person momenta:

p_total = p1 + p2 = 12,000 kg·m/s north - 16,200 kg·m/s north = -4,200 kg·m/s north

In this manner, the combined momentum of the two cars is 4,200 kg·m/s within the north course.