Should that be Violet ? fL = sqrt [( c - v)/( c + v)] * fS
Depends how fast.
Very good. Sad some don't get it.
Reminds me of a similar joke: Driver in court for running a red light and states it wasn't his fault because the light looked red to him. The judge said, "Ok, I'll change this to a speeding ticket, a dollar every mile per hour above the posted speed limit."