Solving Cathode Ray Tube Homework with Mass, Speed & Magnetic Field

[soul5]

Homework Statement

A positively charged particle of mass 7.2 * 10^-8kg is traveling east with speed of 85 m/s. The particle enters a 0.31 T uniform magnetic field, and 2.2 * 10^-3 secounds later leaves the field one-quarter south with speed of 85 m/s. What is the charge of the particle and magnetic force?

Homework Equations

Fc=Fm

mv^2/r=qvB

Fm=qvB

The Attempt at a Solution

I tried but I don't have radius and charge what do I do?

 

[Nabeshin]

I think because they give you a time here you can calculate the period for what would be a complete circular orbit, and then extrapolate the radius. From there, I think you should be able to solve it.