A positively charged particle of mass 6.80 10-8 kg is traveling due east with a speed of 80 m/s and enters a 0.31 T uniform magnetic field. The particle moves through one-quarter of a circle in a time of 1.00 10-3 s, at which time it leaves the field heading due south. All during the motion the particle moves perpendicular to the magnetic field. (a) What is the magnitude of the magnetic force acting on the particle? N (b) What is the magnitude of the charge of the particle?