a$)$ Two point charges one with $Q1=-5\mathrm{.}5{10}^{-6}C$ and the other with $Q2=3\mathrm{.}0{10}^{-6}C$ are positioned $2\mathrm{.}0cm)=(0\mathrm{.}020m$ apart. Calculate the magnitude of the electrostatic force between the two charges using Coulomb's Law, where $k=8\mathrm{.}99\mathrm{.}0{10}^{9}N\frac{m^2}{C^2}.$ Hint: you can use the "PhET Simulation: Coulomb's Law" from D$2$L to help you with this! But show your work!