DISCUSSION THREAD
Hints:
Use your results from the bending moment diagram to determine the location along the length of the beam for the maximum bending moment. Use the flexural stress equation, σ = -My/I, to determine the location(s) of the beam cross-section having the maximum flexural stress.
Use your results from the shear force diagram to determine the location along the length of the beam for the maximum shear force. In order to determine the neutral-axis shear stress, you need to use the shear stress equation τ = V(A*)(y*)/It.
Any questions? Ask (and answer) questions here.
From the hint above, what is the Q in T = VQ/It?
Often, the symbol Q is used to represent the first area moment of a cross-section: Q = A x y, where A is the area and y is the centroid. So, in this particular application, Q = (A*) x (y*). I will change the above Hint to remove that ambiguity and hopefully make it more clear.
Why is A* and y* for the area above the centroid? Why not the bottom area?
Good question to ask. It turns out that if you use the bottom area, you get the same number as the top area, except for a change in sign. I will talk about that in Monday's class.
We are given a hint to find the shear stress for part c, but an email that was sent on Friday says that we do not need to complete part c. Should we ignore this part of the hint or do we need to complete part c?
The hint was provided when the problem was first assigned. Since that time, you have been notified that you are not required to complete Part c).