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:
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The moment of inertia is of the entire cross section;
Substituting, I get
Additional question: Suppose the boards are not nailed, but glued. Find the shearing stress at the joints.
Q and I are the same as above...
