How many electron shells does an atom of oxygen have? (a.) 1 (b.) 2 (c.) 3 (d.) 4

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.

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.

Aball is thrown horizontally from a cliff at 8m/s .in what direction is the ball moving 2s later?