The resultant forces F1 and F2 are shown on the free-body diagram of the subelement. Also shown on the free-body diagram is FH, the resultant of the horizontal shear stress on the bottom of the subelement.
The resultant forces F1 and F2 are shown on the free-body diagram of the subelement. Also shown on the free-body diagram is FH, the resultant of the horizontal shear stress on the bottom of the subelement.