An experimental vehicle slows down and comes to a halt with an acceleration whose magnitude is 9.80 m/s2. after reversing direction in a negligible amount of time, the venicle speeds up with an acceleration of 9.80 m/s2. except for being horizontal, is this motion (a) the same as or (b) different from the motion of a ball that is thrown straight upward, comes to a halt, and falls back to earth? ignore air resistance.