When they start to move,car A exerts a force of 600N on its end of the towrope.The frictional force on car B when it accelerates,is 300N And its masses is 1200kg(a)calculate car bs initial acceleration(b)after a while the cars move at a constant velocity and car A exerts a force of 300N ON THE TOW-ROPE.CALCULATE THE MAGNItude and direction of the frictional force on car B