Ajet stream is a belt of wind in the upper atmosphere that blows around the earth from west to east. how is the jet stream related to the wind direction on the ground?

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.