$9\mathrm{.}81$ and $9\mathrm{.}82$ For the uniform beam shown, determine $($a$)$ the reaction at $A,($b$)$ the reaction at $B.$

AN$.$

Fig. P$9\mathrm{.}82$

$9\mathrm{.}82$

$($a$)R_A=4|w\frac{L}{128}$uarr$|$

$($b$)R_B=23w\frac{L}{128}$uarr;$M_B=7w\frac{L^2}{128}L.$