1. Helical motion of a charged particle A proton (mass m, charge +6) moves in a uniform magnetic eld 13 = ng. At t = 0, the proton's velocity is v'(0) = vmoi + 'Uygj + vzgk. Bmomgwyngo are all positive. The proton subsequently moves along a helical path. Ignore any forces on the proton other than the magnetic force. (a) What is the magnetic force on the proton at t : 0? (b) Does the proton circulate clockwise or counterclockwise if looking down in the +2: direction along the magnetic eld (so k is into the page)? Explain. (c) What is the radius of the helix? (d) What is the pitch of the helix? (The pitch is the distance moved along the magnetic eld direction during one revolution of the proton.)