Solution to Problem 577 | Horizontal Shearing Stress

Where:
$f_v = 200 \, \text{ psi}$
 

$Q = 2 [ \, 2(1)(5.5) \, ] + 3 [ \, 6(1/4)(3) \, ]$

$Q = 35.5 \, \text{ in}^3$
 

$I = \dfrac{4.75(12^3)}{12} - \dfrac{4(10^3}{12}$

$I = 350.67 \, \text{ in}^4$
 

$b = 3(1/4) = 0.75 \, \text{ in}$
 

Thus,
$200 = \dfrac{V(35.5)}{350.67(0.75)}$

$V = 1481.69 \, \text{ lb}$           answer