A proton has an energy of 2.5 × 10−10 J. What force is needed to keep it going in
a circle having a 1.0 km radius
The Attempt at a Solution
so i tried to find v first.
total energy E = 2.5 x 10-10 J =[tex]\gamma[/tex] mc2
so m = photon mass = 1.67 x 10-27
so i found [tex]\gamma[/tex] = 1.66
and v = 0.798c
so when i sub into f = mv2/R , i get f = 9.57 x 10-14
but the answer is 1.6 x 10-13
which means that the photon speed is roughly 0.9++ c
so anyone knows whats wrong?
btw why can't i use E= hf, get f, convert to T =1/f, then use circumference / T = v ?
i realise that v i get is faster than the speed of light. but which step is wrong in this attempt?