A charged ion with a molecular weight equal to 75.0 proton masses and a charge of 1 proton is placed into a magnetic field given by the vector 3i + 12j + 7k. It is moving with a velocity given by the vector -7.0k. wat is the net force and what is the net acceleration produced? What is the net amount of work done by the magnetic field if the field is applied for 20.0 milliseconds? Again I can not remember how to go about doing this problem so could someone please give me a point in the right direction!