Solution 5.4b
From Mechanics
\displaystyle mg=20\times 9\textrm{.}8=196\ \text{N}
Resolving up the plane
\displaystyle \begin{align}
& F-mg\sin {{30}^{\circ }}=0 \\
& F=196\times 0\textrm{.}5=98\ \text{N} \\
\end{align}
Resolving in the normal direction
\displaystyle \begin{align}
& R-mg\cos {{30}^{\circ }}=0 \\
& R=196\times 0\textrm{.}866=170\ \text{N} \\
\end{align}