Find force...?

Question

A magnetuic field (B[with arrow above]) exerts a force on an electric charge (q )moving at a given velocity (v[with arrow above]). The force is the cross product given by F[with arrow above] = qv[arrow above{on v only}] x B[arrow above]. Find a force acting on a proton (q= 1.6 x 10^-19 C) moving at 3/4 speed of light (3.0 x 10^8 m/s) perpendicular to the field.

please show every step of the problem

Answer 1

Better move this to the physics section.