A $20,000lb$ load is transmitted through a column into a $4$ ft by $6$ ft footing with an

embedment of $0$ ft $.$ Find the ${}_z$ at a point

a$.6$ ft below the corner of the footing

b$.6$ ft below the center of the footing

Use the m and n methods as presented in Das or Fig $3\mathrm{.}8($graphical representation$)$ as presented

in your text.