# shear formula confusion

In the notes, the author stated that the shear stress is constant over the bottom face of the segment ... why in figure 7-4 , we can see that the shear stress varies ?

Which is correct ? The red circled part or the figure ?

• In Eq. (7-2), $A'$ is not a constant - it depends on the value of $\bar y'$. You are almost correct - the shear varies parabolically for a section with constant width. For an arbitrary shaped section (e.g. a circular rod, or an I-beam) the variation is not parabolic, but it does satisfy Eq. (7-2). Nov 26, 2016 at 23:17