Agaseous sample of this element is bombarded by photons of various energies in these same units. match each photon to the result of its absorption, or lack thereof, by an n = 1 electron.

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.

yes the answer is total mass in unchanged   : )