Assignment:
The Oh-My-God particle was an ultra-high-energy cosmic ray (most likely an iron nucleus) detected on the evening of 15 October 1991 over Dugway Proving Ground, Utah, by the University of Utah's Fly's Eye Cosmic Ray Detector. Its observation was a shock to astrophysicists (hence the name), who estimated its energy to be approximately 3×1020 [eV].
a) If the OMG particle came to a stop inside of an apple, by how much would the apple's temperature rise?
b) If the Oh-My-God particle were subjected to a uniform magnetic field of B = 1 [T], what would be the radius of particle's trajectory?
If anyone could give me any hints on how to start this problem in the comments section that would be helpful.