4. A 1050kg car is moving westbound at a speed of 15.0m/s on a level road when it collides with a truck 6320kg driving east on the same road at 10m/s. The two vehicles remain locked together after the collision. A) What is the velocity(magnitude and direction) of the two vehicles after the collision? B) At what speed should the truck have been moving so that both it and the car are stopped in the collision? C) Find the change in the kinetic energy of the system of the two vehicles for the situations in part A and part B