1. The problem statement, all variables and given/known data A large wedge rests on a horizontal frictionless surface. A block starts from rest and slides down the inclined surface of the wedge, which is rough. During the motion of the block, the center of mass of the block and wedge. a. does not move. b. moves horizontally with constant speed. c. moves horizontally with increasing speed d. moves vertically with increasing speed e. moves both horizontally and vertically The correct answer was d. 2. Relevant equations None given. 3. The attempt at a solution I reasoned that since the block would begin to slide down the inclined plane, the center of mass of the entire system would shift in relation to the position of the block. Therefore, the center of mass should move both horizontally and vertically.