It doesn't change the conclusion, but note that in a relativistic regime you can't use F=ma because the mass is no longer constant. You need F=dp/dt, where p i

It doesn't change the conclusion, but note that in a relativistic regime you can't use F=ma because the mass is no longer constant. You need F=dp/dt, where p is the relativistic momentum. The Lorentz factor here works out to 1.02, i.e. 510 N, not 500, so not a big effect if I got my maths right.