A cart starts from position 4 in the figure below with a velocity of 16.6 m/s to the left. As shown, h4 = 20.9 m, h3 = 12.0 m, and h2 = 16.6 m. Find the speed with which the cart reaches positions 3, 2, and 1 (in that order). Neglect friction. Let g = 9.81 m/s2.