A proton (charge e, mass 1.67 x 10-27 kg) is fired at a stationary boron nucleus (q = 5e). The proton and the nucleus are initially separated by a very large distance. The proton is given a velocity of 7.0 x 106 m/s. a. Determine the distance of closest approach. [3 marks] b. Determine the force on the proton at its closest approach. [2 marks]