At right, an ice cube (r = 920 kg/m3) floats at rest in water. The cube is 10 cm on a side. 1) What percentage of the ice cube's volume is above the water surface? 2) You push the ice cube down until the top of the ice cube is at level of the surface of the water and then let go. The ice cube then frictionlessly oscillates. a. What net force initially acts on the ice cube? b. What is the "spring constant" for this system? c. The ice cube bobs up and down with what period