A particle of mass 6.0 10-8kg and charge +7.2 C is traveling due east. It enters

Question:

A particle of mass 6.0 × 10-8kg and charge +7.2 µC is traveling due east. It enters perpendicularly a magnetic field whose magnitude is 3.0 T. After entering the field, the particle completes one-half of a circle and exits the field traveling due west. How much time does the particle spend traveling in the magnetic field?