A BMW of mass 1.5 103 kg is traveling at 42 m/s. It approaches a 1.1 103 kg Volkswagen going 27 m/s in the same direction and strikes it in the rear. Neither driver applies the brakes. Neglect the relatively small frictional forces on the cars due to the road and due to air resistance. If the collision slows the BMW down to 36 m/s, what is the speed of the VW after the collision