Would it be feasible to remove the copper outer layer and recover it from solution instead of the zinc core

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.

the answers would be

the first one and the second one