Homework Help: Proton in magnetic field

1. Jan 28, 2013

PZUFIC

1. The problem statement, all variables and given/known data
Proton is moving in the homogen magentic field with B=0,1T. Mass of proton is 938MeV/c02.

How much is the radius of helix at which proton is moving, if his speed is 0,99*c0, and the angle between helix and magnetic field is 60°.

2. Relevant equations
y=$\frac{1}{\sqrt{1-\frac{v^2}{c0^2}}}$

r=$\frac{m*v*y*sin(α)}{c0^2*B}$

3. The attempt at a solution
I have tried to solve it in relativistic way whith equations that I wrote, but the result is wrong. What I am doing wrong?

I hope the post is ok and sory for potential mistakes in spelling and greetings from Slovenia.

2. Jan 29, 2013

clamtrox

I don't understand where you got your equations.

Also, what do you mean "relativistic"? I don't think there should be any gammas anywhere in this calculation: all you use is the Lorentz force $\vec{F}= q \vec{v} \times \vec{B}$.