Blocks a (mass 8.00 kg ) and b (mass 15.00 kg , to the right of a) move on a frictionless, horizontal surface. initially, block b is moving to the left at 0.500 m/s and block a is moving to the right at 2.00 m/s. the blocks are equipped with ideal spring bumpers. the collision is headon, so all motion before and after it is along a straight line. let x be the direction of the initial motion of a.