Thank you, but is that guy correct in calculating the Doppler energy gain to be (1+v^2/2c^2) not (1-v^2/2c^2)?
Also he is using classical kinetic energy to derive the formula, is that appropriate?
http://www.youtube.com/watch?v=hW7DW9NIO9M&feature=player_detailpage
On the above one minute physics video, the guy explained E=mc2 using the idea of Doppler effect, but that doesn't seem right to me, can anyone help?
Thanks very much!