$4\mathrm{.}1$ Study the beam shown in FIGURE $2$ below and answer the following questions:

$50$ kN

$80k\frac{N}{m}$

FIGURE $2$

$4\mathrm{.}1\mathrm{.}1$ Calculate the magnitude of the reactions.

$(4)$

$4\mathrm{.}1\mathrm{.}2$ Calculate the bending moments at the principal points.

$(5)$

$4\mathrm{.}1\mathrm{.}3$ Draw the bending moment diagram.