Question

Please help! I'll give best answer, stars, as many points as I can

A 2,460 kg truck traveling north with a speed of 130 km/hr runs into a car traveling in the same direction with a speed of 89 km/hr.
The mass of the car is 1,225 kg.
After the collision, the two move northward together as one mass.
What is the speed of the wreck?

A) 13.4 km/hr

B) 120 km/hr

C) 22.7 km/hr

Answer 1

Momentum is always conserves in a collision, so 2460*130 + 1225*89 = total momentum. After the collision, you can treat the two vehicles as one mass and divide momentum by mass to obtain velocity. 428825/3685 = 116.37 km/hr. Closest answer is B