A particle with a +5.0 µC charge and a kinetic energy of 0.090 J is fired into a uniform magnetic field of magnitude 0.30 T. If the particle moves in a circular path of radius 3.0 m, determine its mass.

Answer 1

find the force for the charge with that velocity in that magnetic field, you have an equation for that.

Then centripetal force equals that force above, solve for mass