BEFORE COLLISION 300 kg 1 200 kg 2 000 kg Ooo 0 AFTER COLLISION (2) (5) (4) 7.1 Write down magnitude and direction of the 'reaction force' to the weight of truck A 7.2 Calculate the velocity of truck B after the collision 7.3 Calculate the magnitude of the force that truck A exerts on truck B if the collision lasts for 0,5 s. 8 The most common reasons for rear-end collisions are too short a following distance, speeding and failing brakes. The sketch below represents one such collision. Car A of mass 1 000 kg, stationary at a traffic light, is hit from behind by Car B of mass 1 200 kg, travelling at 18 ms Immediately after the collision Car A moves forward at 12 ms!