an object has a variblle volume and shape before it changes state. After the change, it can still change in shape but has a fixed volume. which change of state has occured?

You throw a small rock straight up from the edge of a highway bridge that crosses a river. the rock passes you on its way down, 7.00 s after it was thrown. what is the speed of the rock just before it reaches the water 28.0 m below the point where the rock left your hand? ignore air resistance.