The post is made of Douglas fir and has a diameter of $100 \mathrm{mm} .$ If it is subjected to the load of $20 \mathrm{kN}$ and the soil provides a frictional resistance distributed around the post that is triangular along its sides; that is, it varies from $w=0$ at $y=0$ to $w=12 \mathrm{kN} / \mathrm{m}$ at $y=2 \mathrm{m},$ determine the force $\mathbf{F}$ at its bottom needed for equilibrium. Also, what is the displacement of the top of the post $A$ with respect to its bottom $B ?$ Neglect the weight of the post.