Proton's Velocity 1. The problem statement, all variables and given/known data What is the speed of the proton? 2. Relevant equations B=u0qv/(4pir^2) 3. The attempt at a solution I rearranged the equation so that I solve for velocity, v. I determined that r^2 is 1.8*10^-5 m. I plugged in 1.1*10^-3 for B. The q for the proton is 1.6*10^-19. Plugging all that and the constants in gave me a velocity of 1.2*10^8 m/s.