F = kq2 / r2 q = ne F = k(ne)2 / r2 n = âš(r2F / ke2) = (r/e) âš(F/k) k = 9 x 109 Nm2/C2 e = 1.6 x 10-19 C n = [(4.2 x 10-10) / (1.6 x 10-19)] âš[(5.2 x 10-9) / (9 x 109)] ≅ 1.995 ≅ 2
<span>A = 4.7 + C where A represents the students who got A's, and C is the number of hours that the C-grade students spent on homework per week</span>