Michel Jullian wrote: > P.S. Oh yes I had forgotten my promise to Harry below, my comment was that > mv^2/r for the satellite can be thought of as a centrifugal force or as a > centripetal acceleration times mass depending on the frame (it changes sign > while going from the F side to the m*a side), but not as a centripetal force > as you had put it. The centripetal force here is gravity of course.
Let m be the mass satellite and M the mass of the earth. You can only use mv^2/r in the frame where the Earth is stationary. If you are allowed to use it in the frame where the satellite is stationary then logically one could argue the satellite is able exert force on the Earth of Mv^2/r, which is absurd. Working with some aspects of a theory and ignoring others may prove productive for a while, but sooner or later you need to owe up to logic. Harry
