A: The shear stress on each bolt is the vector sum of two separate components: the direct shear force (F/4 upward at each bolt) and the torsional shear force (equal magnitude at each bolt, perpendicular to the line connecting each bolt to the pattern centroid). The critical bolts are determined by how these two vectors add together — when the direct shear and torsional shear components point in similar directions, they amplify each other, making those bolts most vulnerable. You must resolve both force systems independently and then perform vector addition to find which bolt sees the largest resultant force.