C.35, C.36

$${\begin{align*}\frac{F}{\varepsilon m_\text{total}} &= \frac{\frac{1}{2} c_d A \rho v^2}{\varepsilon \rho \frac{2}{3} A L} \\&= \frac{3}{4\varepsilon}c_d \frac{v^2}{L}\end{align*}}$$