A railway truck A of mass 2000kg moves westwards with a velocity of 3m. s. it collides with a stationery truck B of mass 1200kg, loaded with electronic equipment of mass 300kg. The two trucks combined after the collision. Ignore the effects of friction. 7.1 wite 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 0.5s