A proton having an initial velocity of 18.1 Mm/s enters a uniform magnetic field of magnitude 0.330 T with a direction perpendicular to the proton's velocity. It leaves the field-filled region with velocity -18.1 Mm/s.
(a) Determine the direction of the magnetic field.

(b) Determine the radius of curvature of the proton's path while in the field.
m

(c) Determine the distance the proton traveled in the field.
m

(d) Determine the time interval for which the proton is in the field.
ns