[MUSIC] This is Module 33 of Mechanics of Materials part III. Continuing design of the bean that we've been working on for the last several modules. We've selected this wide flange I-beam with the section module is shown. We've checked now the maximum flexural stress experience at the extreme fiber at point A. Next we're going to check in this module the transverse shear stress experienced at the neutral axis where maximum transverse shear stress is occurs, and that's point C. And then in the next module, we'll check a combination at point B of flexural stress and sheer stress. So for the maximum transfer sheer stress, what's the formula that we use for that at point C? You should recall back, transverse shear stress we developed earlier. And if you need to go back and review, please do that. We're going to need the V max, the maximum shear force experienced along the length of the beam. And so how will I find that? And what you should say is, we should go back to our shear force spending moment diagram and looking for the maximum shear force experience along the length of the beam it appears to be in this first section over here and it's equaled to 175.5 kN. And so now we have V max, we know what I is for a cross section. At point C, we know what the width is, 6.9 millimeters. And so we still need Q, or our first moment of outer area and so, try to calculate that on your own. And so Q is the first moment of outer area, in this case, we're going to break down the outer area from the neutral surface or the neutral axis, into two standard shapes. The first one is the web portion here. And so the Y bar to it's neutral axis is 166.2 divided by 2 times it's area which is 6.9 times 166.2. Then I have to use the other standard shape which is the flange. Y bar to it is 166.2 plus 9.8 divided by 2 and then we multiply that by the area of the flange which is 171 times 9.8 and we get a Q equal to 382,000 millimeters Q. And so we have pretty much all we need. We have maximum shear force that's experienced on our beam. We know what Q is for the cross section, we know what I is for the cross section, we know what B is and so we substitute those in, we can calculate what the shear stress experienced is, it's 80.3 if you recall back the allowable shear stress which we found in previous modules was 104.6 megapascals, and so, again, we are okay with this beam being selected for the critical check at the neutral axis or point C. And so, we'll come back next time and check the last point which is the junction of the flange in the web. [MUSIC]