Shear force and bending moment diagrams example #4: applied moment

[@jameshibbitts6383]

Your videos are absolutely amazing!!! If I wasn't, ya know, a broke student I'd be donating so much. I'll remember you once I graduate though!!! People like you are what keeps the world moving, honestly. Keep up the good fight!!!!

[@Engineer4Free]

Haha thanks James :). Donations are nice, but positive feedback like yours is what really motivates me to keep going. Glad you like the videos, do tell a friend that could use them too!!

[@andrewamato865]

At uni they taught us the rules. They never broke it down like this on how to create your own equations. It was all the area stuff. This is great. Thanks.

[@Engineer4Free]

Thanks for the feedback Andrew. This is like a more visual approach to the actual derivations that are happening between the diagrams, but totally valid and much quicker =) =). It only reveals the key values (at changes in slope/discontinuities), and the general shape of the chart between them, but thats almost always good enough! I got some videos on the long way, but they're no fun

[@geerwaanreddy6398]

Thankss for this I m gonna pass my exam coz of this

[@Engineer4Free]

Woohoo, hope it went well!!

[@Finn-rt5yx]

Will there be any sort of vertical displacement at where the concentrated moment is applied?

[@Engineer4Free]

No. Because of symmetry, the midpoint of this beam should remain undeflected. The beam would deflect upwards on the left hand side, and downwards on the right hand side.

[@Finn-rt5yx]

@@Engineer4Free Cheers man

[@sachynk8923]

Love the way you explained thanks bud

[@Engineer4Free]

You're welcome Sachyn, thanks for the comment =)

[@JakeVoorhees]

Thank you so much for your videos, love the movement. I found you from Reddit this AM. I run a community for young engineers teaching career advice and how to be successful once you have good grades, which is what you help with. I'd love to collab with you somehow. Cheers man!!

[@Engineer4Free]

Thanks for reaching out! Love what you're doing, I PM'd you on Reddit :)

[@JakeVoorhees]

Great, thanks!!

[@JakeVoorhees]

cool man i replied!! im still in awe about your 2M+ reach such a ballleerrrrr

[@Matt-sn7fb]

sir could you please explain me how to determine the sign of concentrated moment ?.. I'm out for considering it myself, because in many cases, many tutors said that it depands on whether It's C.W or C.C.W. But other tutors said It's not.

[@Engineer4Free]

Hey I think I explain it better in the following videos than I would in text. Check out videos 66, 67, & 71 here: engineer4free.com/statics lemme know if you're still unsure after!

[@sainandan65]

what should i answer if some one asks what is the moment @ mid point of beam?

[@Engineer4Free]

That would be a dirty trick question. Mathematically, it’s D.N.E. (Does not exist). But I would write a small paragraph explaining the magnitude and sign just to each side of the midpoint, and then also mention that it’s a dirty trick question 🤔

[@gartonb1]

Thank you! thank you thank you thank you !!!

[@Engineer4Free]

Jahhhhhhh welcome 🙌

[@mohammedtalhami3225]

Thanks man! love your videos so much

[@sashinmoodley6674]

Hi, what would be the magnitude of the maximum bending moment for the beam?

[@Engineer4Free]

In absolute terms, it would be 50 kNm. If your asked specifically for the max positive or max negative bending moment, the max positive moment is +50 kNm and the max negative moment is -50 kNm.

[@hacknoclub2046]

hey great videos and which stylus pen are you using for writing ?

[@Engineer4Free]

Hey thanks!! It's a CTL-470 bamboo wacom thats about 6 years old :p I keep a current list of all of my hardware and software at engineer4free.com/tools it's a pretty short list but its all there

[@classicsalted]

i didnt understand how sigmaMA = 100 kNm. Please explain

[@Engineer4Free]

Oh sorry, I skipped a step. ΣMa = By(4m) -100kNm = 0 .... it can then be simplified to By(4m) = 100kNm. The term with By is positive in the first expression because By causes a positive moment about A, and the applied moment is negative because it creates a negative moment about A. Hope that clears it up ✌️

[@mesfinray]

keep up

[@muhammadusman439]

Why is reaction Ay downward?

[@Engineer4Free]

If you grab the beam in the middle with your hand and twist in a clockwise motion, the beam is going to want to rotate clockwise. As a result, it is going to be pushing (down) into the support at B, and pulling (up) at the support at A. The reactions "react" to this by applying equal and opposite forces to prevent this rotation from actually happening and keep the beam in static equilibrium. If the beam is "pulling up" on the reaction at A, then that means the reaction at A is "pulling down" on the beam at that point A. Does that clarify it?

[@muhammadusman439]

sure, understood your explanation, thanks for your time.

[@SumanthLazarus]

I was sorta getting the concept before reading your explanation. Now I want to give you a kiss on the cheek for this, kudos!

[@albertalink]

your negative 50 under looks like "-90". Anyways, thanks for your video.

[@Engineer4Free]

Thanks Kevin!!! =)

[@palaksingh3492]

I don't understand moment direction can u help me sir please

[@Engineer4Free]

Ok, I really recommend that you watch videos 66-72 here: engineer4free.com/statics and then move on to videos 1-9 here: engineer4free.com/structural-analysis . Watch them in this order, because you’re currently watching from the second set, and it is a shortcut method. LEarn the long way first, then the shortcut will make more sense.