When concrete is poured into forms, the forces on the forms can be estimated by assuming that the freshly poured concrete behaves as a liquid with a specific gravity of $2\mathrm{.}4.$ The forms for a long concrete wall $4$ inches thick and $8$ feet high are held together by bolts spaced every $2$ feet, as shown in the drawing. The bolts are right at the top and the bottom of the concrete. What is the force in each upper bolt? In each lower bolt? State clearly whether each bolt is in tension or compression.