1. The problem statement, all variables and given/known data Here is the question with the solution: 3. The attempt at a solution I understand the first part where they find the forces by summation of moments. However I don't understand how they got that area. Why would they take the diameter (0.016) and subtract it from the length (0.036)? Aren't you suppose to use the area of the link that is parallel to the force. In other words, use the area (0.008) * (the thickness of the link which is not given)? For example if you were pulling a cylindrical rod you would use the area of the circle to find the stress and not the surface area of the sides of the cylinder.