A 2.2 kg mass starts from rest at point A and moves along the x-axis subject to the potential energy shown in the figure below. PE Press F11 to exit full screen A 30 J. E 25 J C 20 J 15 J D 10 J 5 J B X 2m 4m 6m 8m 10m (a) Determine the speed (in m/s) of the mass at points B, C, D. (For each answer, enter a number.) point B 4.77 m/s point C 3.01 m/s point D 3.69 m/s (b) Determine the turning points for the mass. (Select all that apply.) O point A O point B O point C O point D O point E