(Two boxes are tied together by a string and are sitting at rest on a frictionless surface. Between the two boxes is a massless compressed spring. The string tying the two boxes together is cut and the spring expands, pushing the boxes apart. The box on the left has four times the mass of the box on the right. a) After the string is cut and the boxes lose contact with the spring, will the magnitude of the momentum of the box on the left be (a) greater than, (b) less than, or (c) equal to the magnitude of the momentum of the box on the right