You are designing an amusement park ride. a cart with two riders moves horizontally with speed v = 4.00 m/s . you assume that the total mass of cart plus riders is 300 kg. the cart hits a light spring that is attached to a wall, momentarily comes to rest as the spring is compressed, and then regains speed as it moves back in the opposite direction. for the ride to be thrilling but safe, the maximum acceleration of the cart during this motion should be 3.00g. ignore friction.