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Hanson you didn't give us any dimensions oh no let's make them up okay this looks like two meters and then that looks like four meters and then this one over here again two meters okay how's that I just made that up but we can do that we have the power okay so let's see three kilonewtons per meter over four meters that would be the same as twelve kilonewtons right and this again you just look at the area of that shape there okay so we got what we need let's find global equilibrium let's take a moment and a okay summing the moments at Point a equal zero equals what okay I've got this 18 which rotates me negative so minus 18 I'm so far away two and then I've got this 12 which rotates me negative 12 minus 12 times how far is that it's 2 and it's in the middle of this 4 so 2 plus 2 more that would be 4 and then b1i rotates me oh that's positive so plus B Y times 6 and then the 6 over here rotates me negative so minus 6 times 8 right okay and so there B Y is equal to drumroll please let's say that's 36 that's 48 that's 48 48 48 48 96 96 and 100 and and that's 132 in it Claire Claire 9 6 plus 36 132 divided by 6 equals y2 so B Y would be 22 kilonewtons okay so that's you you're 22 kilonewtons okay and then and then any Y over here remember the up stuffs got equal to down stuff so what do I have going down I got 12 plus 18 is 30 all right plus 6 more is 36 and 36 going down I got 22 going up so I need 14 more Donna okay there you go so now we have our global equilibrium that's step one done okay the next thing we need to do and if you do this on on a digital homework the first thing that you do is draw what we call discontinuities the equation or the load changes here and it's not continuous here it there's a big jump there's something going on right here and we call those discontinuities and I just say let's draw some line everywhere we think something interesting is gonna happen so I think something interesting is going to happen here okay these are Co my discontinuity lines okay I think something interesting is going to happen here okay now I did not put anything here this is a distributed load it is not a concentrated load we changed it to a concentrated load only to help us find global equilibrium after that forget about it it's got to go back to a distributed load because it is a distributed load because the distributed load plots differently than a concentrated load does okay we used a little simplifying technique to find global but now we got to undo it we got to get it out of her mind okay and the last discontinuity is over here at the very end of the beam okay so there's our lines okay where I think something interesting is going to happen okay now the next thing we're going to we're going to start here we're going to plot our V diagram and we'll plot this next because this one depends on this one so we got to get this right now here's the thing this is the shear force so what is this sum of the forces on that beam zero so whatever we do here on this graph we better wind up over here at the end we better wind up back at zero if you don't you've missed something up what about em what is the sum of the moments on a beam it's zero so again on this graph if you don't wind up at zero you've done something wrong and if you don't get back to zero on this or this right then where's the mistake the mistake is right here it's a global equilibrium it almost always is global equilibrium okay go back and check your global so that's the nice thing you shouldn't miss these problems because you want to nut back at zero and if you don't then you're like well something's not right okay it needs to wind up at zero alright so imagine this I'm fixing to get on this beam and I'm gonna walk across it from the left to the right okay I'm gonna hop up here and start walking across it okay but I got me a load backpack on I got my backpack on it's completely empty as I go across this beam people are gonna be putting things in my backpack right that's these loads that I'm that I'm gonna incur across this beam as I go as I go along so let's if we can graph the V diagram alright here we go we hopped on the beam the first thing we get in our backpack BAM 14 kilonewtons up that's a that's a van halen force right there might as well mmm jump go ahead and jump nope I hope they don't give me YouTube will find me for using music right maybe it won't recognize it probably not okay so here we go 14 kilonewtons that's where we are and we don't have to put the units on these because we like we have the units on our whole entire graph here don't we so let me just make that big enough where you can see it 14 okay all right now just keep book anything gonna happen here we go walking no change no change no change no change BAM oh 18 if a backpack down well I was that 14 puzzle but now you took put 18 in there so where am I now whoop I'm at negative 4 okay straight down BAM another one made me jump didn't it all right now from there I've got to go down 12 more and how do I go down 12 well I take a step I get three take another step I get three more another step I get three more so I'm going down down down down that's why it's a straight slope so I'm at four by the time I get over there I'm going to go down 12 more so I'm going to be at BAM negative 16 and how do I get from there to there again I've got a straight across the line so the next graph down has to be a straight slope right so like this that's pretty straight now what happens well BAM sick got another jump here 22 well that's gonna take me 22 let's see that's gonna take me up here to positive 6 so here we go okay let's walk some more no change no change no change BAM into the beam John Denver force take me home to the place I have a long Oh Monsieur graph back to zero there you go that's too silly you're so silly hey man if it helps you remember to do how to do these graphs then I'll sing to you I don't care okay so we got our V diagram that's it so if I ask you what is the biggest shear force on that beam you would say dude it's 16 because there's a designer I don't care if the forces this way or that way right I just want to know the magnitude of that worst case scenario on this beam it's 16 okay so the next thing I do on this is I put me some little pluses and minuses okay plus minus plus okay anything above the line gets a plus anything below the line gets a negative and that tells me what the slope is gonna do on this next line down here okay so that tells me that on my M diagram is gonna go uphill downhill and then back uphill okay so that's what that slope is now here's where the graphic method comes into play we're gonna look at these shapes that we made here okay because the height of these shapes are in wood the height is in kilonewtons and the width of these shapes is in meters so if I find the area of that shape it would be height times width which is kilonewton meters which is a moment so the area of these shapes gives me the moment that I'm gonna use on that next graph okay so I like to do these and put a little circle around and for instance this is 2 times 14 so this area is 28 so I'll put a little circle around and that tells me that that's his area now this guy is made up of a rectangle in a triangle right the triangle is 4 times 12 is 48 divided by 2 is 24 that's 24 and this part here is 4 times 4 is 16 so the area of this guy is 40 okay and then finally the area over here is what 6 times 2 12 okay so there's my areas I'm ready to do my moment diagram now ok so here I am I'm starting at 0 the only time you don't start at 0 is if you have a concentrated moment here and you can watch the next video and I'll show you how to deal with concentrated moments really a nice trick another little saying for you to remember in the next video it's a treat you've gotta go see ok so here we go we're starting off at zero we're gonna go up hill how much twenty-eight okay we go to zero we got a twenty eight there's 28 right there how do I get from there to there well let's see that one will straight across so the next one is gonna be straight slope this is not hard is it okay BAM then I gotta go downhill forty I'm at twenty-eight that's gonna take me to negative carry the nine twelve okay so here I am negative twelve how do I get there oh oh this one is a slope II do the next line down is gonna be parabolic why is it parabolic we're gonna take a step over here and get four then the next step I get something more than four and then something more than that and then more and then over here I get sixteen right so I'm not accumulating load linearly I'm accumulating it parabolically and so what here's what we do I have to go from here to there so I'm gonna give you two choices okay and that's this or this okay now this is the number one mistake students make is choosing this inflection here wrong or incorrectly okay but I'm gonna teach you a little trick that gets it right every single time and it goes like this okay I take a step over here what do I get shortstack well now if I take that same step over here what do I get fat stack okay so I'm accumulating load slowly over here and quickly over there so I call this slow to fast now that this was flipped around the other way it would be fast to slow so I'm gonna ask you this every time is it slow to fast or fast and slow right which one is it and I want you to think you're going snow skiing right what does slow then fast look like on a on a mountain slope right slow is like body slope that's like almost flat right and then fast Black Diamond has steep man so here we have slow then fast so which one of those curves is smooth and fast this top one is isn't it bunny slope black dumb and this one right here is fast or really steep and then slow which is not so steep so we would choose that top curve okay so we would choose the top one which is slow then fast okay there you go I hope that makes sense you will never get it wrong if you do it like that okay now you're at negative 12 do we have a John Deere for a moment I am 12 what that's going to take us back to zero because it goes uphill right and how do I get there we'll have a straight so I'm gonna have a straight slope BAM there you go folks look at that man are we good at this stuff or what okay so what's the max moment on that bean 28 kilonewton meters that's the maximum moment on that beam okay there is your introduction to the graphic method like I said stay tuned to the next video and I'm gonna throw at you the same thing but I'm gonna also throw at you some moments on there and it makes a little bit of difference so hang on and I'll see you next time thanks guys