a) The horizontal shear per unit length q is VQ/I, where q also equals the shearing force divided by the horizontal shear distance. To find V, q, Q, and I must be computed.
Q is the moment of the area above the shearing
plane:
 |
|
The moment of inertia is of the entire cross section;
Substituting, I get
b) The maximum shearing stress occurs at the N.A., not the nails. So Q must be recalculated:
The thickness t is the thickness of the wood, or 2(3/4) = 1.5 in. The shearing stress is
