Construction workers were raising heavy steel beams up 10 meters, unfortunately, they dropped them. as the beams fell towards the ground the energy they possessed at 10 meters above the street was converted into energy.

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.