In the quark model of fundamental particles, a proton is
composed of three quarks: two "up" quarks, each having charge
$+2 e / 3,$ and one "down" quark, having charge $-e / 3 .$ Suppose that
the three quarks are equidistant from one another. Take that separation distance to be $1.32 \times 10^{-15} \mathrm{m}$ and calculate the electric
potential energy of the system of (a) only the two up quarks and
(b) all three quarks.