In class we learned that particles and radiation field can exchange energy, but the total energy needs to be conserved. find out whether a non-relativistic free electron can absorb a photon from a light field. to that end set up total (electron and radiation field) energy and momentum conservation relations by assuming that the electron velocity changes from v to u after a photon with energy ω and momentum h. k =h a/c has been absorbed. can both energy and momentum conservation of the electron-photon system be fulfilled at the same time?