[structures] The bending moment, $M(\mathrm{kN} \mathrm{m})$, of a beam of length $8 \mathrm{~m}$ is given by
$$
M= \begin{cases}2.16 x & 0 \leq x<5 \\ 28.8-3.6 x & 5 \leq x \leq 8\end{cases}
$$
where $x$ is the distance along the beam. The shear force, $V$, is given by $V=\frac{\mathrm{d} M}{\mathrm{~d} x}$. Sketch $V$ for $0 \leq x \leq 8$