Statics: Lesson 50 - Trusses, How to Find a Zero Force Member, Method of Joints

[@khukuri9123]

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[@zhiarmustafa]

You don't know how good a teacher is until you lose'em Like your's 🙂

[@ihaveseverefrootsnackism]

Exactly. My current teacher (in a related course that uses all this stuff but higher level) is pretty nice, but the stuff is just tough. And this stuff... I can sit there for 6 hours not knowing something going across all sorts of resources, then sit here and in 5 minutes learn a crap ton on these videos. I started watching this channel almost 2 years ago and am still dumbfounded by how well it works.

[@tyrellaxe8841]

Too bad yours made you cook meth 💔

[@Cooldibs]

Had him as a professor, he was great!

[@johnsichone679]

school would have been easier

[@Glorvox]

The fact that he solves the problem with us is what is so helpful to me. My professors use old solutions that sometimes have errors and they just say "this equals so and so" expecting me to know how they arrived at their answer. Dr. Hanson, thank you for TEACHING us your ways. I would be so lost without this channel.

[@zacksram]

Yo fr bruh, the exact same as me

[@StuartZiane]

"let's just do a couple of joints, and we're gonna be there!" - That's priceless! :D I wish my lecturers had been able to explain how to find a zero force member as well as you have. Many thanks!

[@leechilton7684]

you are saving me. in statics. i love you. you are so hilarious and helpful and you’re so good at breaking these things down to be understandable and manageable questions. i love your mantra that you say, when you talk about where it gets difficult, and you’ll say “but that’s okay, because i’m here with you!” you make these problems seem so not daunting and so much less intimidating. i wish every teacher was as incredible and funny and kind as you!

[@johnsichone679]

i love the way you simplify school,you make it easier....none gets bored with the way you teach

[@pinkhead6857890]

Learning statics is literally the only reason why I went to university, and here I am back to watching KZbin videos to learn its anyway! Subbed. This is so much more useful than mindlessly memorizing trigonometric identities and functions just so you can write a series of equations to prove that the sky is blue.

[@georgesadler7830]

DR. Hanson, thank you for solving a mammoth Trusses and Zero Force Member problem in mechanics. The explanation for this example is outstanding.

[@williamwallacevegim9576]

I just passed my Civil Engineering Licensure Exam this November, and I just want to Thank You sir Jeff! Your lectures have made my Engineering life a lot easier!!!

[@danielpaul460]

I am mechanical engineering student this video has helped a lot.may God bless you Dr Hanson

[@flunknuts6260]

I love this class because you actually teach us the tricks and that’s all i needed

[@Forever-fun]

Where you from

[@gomo88]

@@Forever-fun creep

[@richardturietta9455]

Studying for my PE, this is great.

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I am a special inspector right now for geo tech firm, once I get my EIT, will I get a raise of 5$?

[@ethanboba5262]

@@alfonsoperez1762 Nope, you just get a pat on the back and bragging rights

[@alfonsoperez1762]

@@ethanboba5262 just more responsibilities lmao

[@rafidhasan5882]

You're such an amazing teacher, sir. Wish I could meet you.... Thank you so much for the amazing lessons, you helped me a lot

[@jasminerichards4159]

I really enjoyed this this playlist , all the lessons were fun & engaging , thank you

[@ambrose_8]

Can anyone confirm this alternative way of solving for KD and KJ: @12:20, we could instead rotate the axis so that x and y align with KD on the y-axis and KJ on the x-axis, and then solve from that?

[@Legend-ee2tj]

I think typically we can't do that cause KD and KJ aren’t perpendicular

[@Caroline-ot8jn]

Love the optical illusion on your shirt, not dizzy at all lol

[@nicholashung5923]

Great video Jeff, I was so confused about zero force members and you did a great job explaining and solving the problem! Keep it up!

[@multifanheresostopfanwars3996]

3:39 I didn't know this. Thank you, sir!

[@mukhtarabdi4443]

You helped us a lot.Thank you professor Jeff Hanson

[@terrancepage9163]

4:44 is actually crazy. He asked a question, looked at me to answer, and I answered "LB for starters!" He was like yea ok LB. What an incredible teacher to be able to read his students without even talking to them. insane

[@frankhao8439]

error at 15:01, it should be minus 0.447KD, not plus

[@samoiahrussell7844]

Yess

[@J-Sade]

I used Jeff's videos while in my statics class, and here i am again studying for my FE. Still one of the best Professors on KZbin.

[@owlislike]

I have a very nice professor, however we have never gone over how to visually identify zero force members. This is amazing stuff.

[@evelinageorge2997]

Oh now I agree the fact that to be de best is just being able to express clearly what u know and not just knowing😃.Salute sir💃💃💃

[@thedestroyer8956]

we would all have been straight top of all our classes had we have this type of teacher

[@Kiros-r1q]

amazing teacher with amazing subject

[@EngSeifHabashy]

this guy just rescued before the engineering statics quiz

[@manuboker1]

Wonderful statics lessons!! really taking the time to explain the problems along with a good sense of humor :))

[@ihaveseverefrootsnackism]

Would have prevented myself from getting a quiz question wrong if I'd just watched this yesterday. smh xD Very helpful for the near future! Structural analysis feels like statics all over again but on steroids. thanks

[@ronin395_]

Legend!! Thanks for helping me get through undergrad and onward!

[@garypoplin4599]

1:09 - I suppose I’m already supposed to know this; but, how were the loads determined? Are they calculated?

[@BS-yl7jv]

Hi Jeff, thank you very much for the video. Well explained 🤟

[@odysseasdemetriou5075]

You have helped me so much with these videos professor! Thank you so much!!! :)

[@matthewclark7209]

Me about 10 hours before an exam: maybe this truss thing is interesting

[@dirtmoto2780]

Lmao I got a statics exam in 2 hours and am totally banking on this guys lectures to carry me through it.

[@sebastiancurry3714]

@@dirtmoto2780 Update? How was that exam?

[@dirtmoto2780]

@@sebastiancurry3714 not great got a 65

[@sebastiancurry3714]

@@dirtmoto2780 its all good bro, thats not even that bad. If you would of started studying sooner, like a week or even more instead of 2 hours before you would of got an A most likely, keep grinding bro!

[@dirtmoto2780]

Yes sir! I really slacked during this summer semester, but I am ready to kick some ass in the fall!

[@samuelirwin8206]

thank you for explaining the steps and showing how they apply properly. this theory will help me in my quiz. tho i like my professor as a person....he doesn't teach very clear....this helped a lot! Thank you so much!

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You're such a powerful tutor

[@MdAlvi-cw3bn]

You make this topic so much easier for me ❤❤

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You're a god tier teacher!

[@jackychau3024]

Such an excellent teacher!

[@TaniaDTV]

Why you were not my professor in school? your videos are the best!

[@multifanheresostopfanwars3996]

5:02 I love the BL~

[@osuwatchdog7154]

Thank you Dr Hanson you made my life easy. I wish you were in my college.

[@ahmadwalid9070]

thank you professor , this vid was really helpful with visualizing zero force members i was struggling at ❤❤

[@andrewmorrissy3122]

insanely good statics man!

[@Peter_1986]

I can't believe he actually solved this entire problem.

[@idowumichael-if4if]

Thank you sir for this lecture 13:10

[@charlessherer7155]

Jeff, I literally love you

[@rawaazahaf9878]

Thank you veryyyy much I'm from Algeria ❤️🇩🇿🇩🇿

[@gp7493]

I bit confused on 17:12, so because it's negative it's compression?

[@ralphbarbato5447]

Compression is when the force is acting towards the joint; He assumed the member to be in compression so it ended up being a positive value. Typically when you don't know which direction the force should go, you can assume Tension and then any negative values would indicate that the member is in compression.

[@Zzzzzzzzz678]

Wow, 20mins for that scary truss! It would've took me all the time of the exam😂😂😂

[@UrBadChoices]

The hero we needed

[@kahyanamuneku5298]

Why didn't we incorporate Ax when finding the sum of forces in Fx for AB?

[@ThePorkTree]

i had the same question, but i doubt itll be sorted by the time i have my exam tomorrow, hah.

[@abhijitsinghrait]

Had the same query. Likely because its a symmetric truss and we have the roller on one side (where reaction would only by along y-axis), and there are no external forces in x direction. Therefore on the pinned connection, the reaction along the x-direction would be zero.

[@wengangdit]

I love the way u explain the problem

[@AsemhiaPeter]

woow, such a great tutor ever found, God bless you sir.Please how do I access your study materials

[@World084]

Thanks 😊 our teacher❤❤

[@jamescuarteros7478]

Thank you so much! OMG now I can solve my exercises easily

[@dstutz54]

Can you take sum of moments when solving by method of joints? Or can you only use sum of forces in the x-y direction at the joint in question?

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bro be my professor i love it

[@AnnalisaSihako]

I'm so content with your videos..,🤝💙👍❤️🤟

[@aminaghoo]

Thank you so much, Professor, you are the best 💜💜💜

[@icebag5388]

19:50 you don't need to subtract 20 kN force?

[@zunaidhassan9662]

If I understand it, 20kN is not acting on joint J but on joint D so it's not considered there.

[@Tropezz]

7:44 how did you know it was 45?

[@Leen-pv4yq]

Thank you a lot ❤

[@fontanillacarlamariellie.7261]

Thank you sir. It helps.

[@isaacokplogidi8012]

I love your lectures Sir

[@AlejandroSanchez-dw5iv]

Why at the end you did not count the force in the Y direction going down that is equal to 20 KN and will make JD be 13.3 KN? Please let me know if it was just a little mistake or I am missing something.

[@robertrobayo5744]

Idk if you still need this but if we do the FBD at joint D and do the sum of the forces in the y direction it would be [DJ - 20 - 7.46sin63.4 - 7.46sin63.4 = 0] Therefore DJ = 33.341 It looks like you forgot to add the 20KN force

[@HaboonOfficialChannel]

​@@robertrobayo5744Thank You So Much Pro You Saved Me❤

[@samansoltani-f2k]

i love thid class😍😍❤🧡❤❤

[@lailad838]

Is no one gonna talk about how perfect his dotted circles were

[@DecoderDibakar]

Sir love from Bangladesh

[@ohyfrnz]

How do I identify if EQUATION 1 is for KJ and EQUATION 2 is for KD, when using the system solver? Thanks.

[@kakoy52]

this really helped me thank you!

[@Chalizdekino1]

I hope I finally find my answer. I am confused I have read almost the whole day. Adult education is indeed hard.

[@kjartanasger]

He used to have this wooden truss system model or something. Anyone know which video he uses it in? or perhaps where to buy something like that? I'd like to have some models to play with so I don't have to imagine everythng in my head :-)

[@lilsourmango]

If i calculate Moment in G, I have 10KN*8m + 20KN*6m + 10KN*4m - Ay*12m, where Ay=15KN. Although it makes sense to have both Ay and Gy be 20KN each, the formula gives a different result. What am I missing?

[@Jasmine-lg6xb]

Today is my statics final exam fellas wish me luck😢 I’m shitting myself rn ngl

[@egaborjoshuaikechukwu7042]

Hope you did good Blessings from a complete stranger

[@MatthewHarmon-m8i]

At Joint K; when inputting the two unknowns and two equations into the matrix calculation, how did you know which values belonged to either KJ or KD?

[@munderabukhder9022]

you can actually subtract the equations from eachother (KJ gets removed this way) and solve for KD. then substitute KD into either of the initial equations to get KJ. thats how I did it, since I have no system solver

[@satoukazuma1885]

excuse me sir Jeff how did you get the KJ and the KD i dont quite get it what you input in your calculator

[@zunaidhassan9662]

They're simultaneous equations. Scientific calculators can solve them.

[@alandeutsch9987]

what happens when there's loading on the top?

[@joshpedrigosa5401]

you are the best sir!!!

[@sagewaterdragon]

This was an amazing video, thank you, I wish my professor was as good at teaching as you are.

[@yourpapa6641]

What about Ax when calculating forces in joint A?

[@Amanda-bg7ib]

this was so exciting

[@mark7foran]

For KJ and IJ you have it = 23.57kN C, but then on the FBD for joint J the arrows are in T. Just a little confused.

[@bobbyfirmino7758]

15:25 He should've written 30 instead of 10 and KJ will be equal to 51.675 KN

[@richardturietta9455]

Thank you so much, great review!

[@saisusmithareddydevarinti5463]

How do we know whether kj is acting inwards or outwards??

[@chomusuke1013]

Professor Hanson: Cuts it in half Me: Panics but in half

[@notme831]

Sir at point A why it only has vertical reaction and not horizontal(Ax) it is not roller support

[@mihrabanjabar1244]

Thanks for this video ❤

[@zjyub]

I don't know if you are still answering questions on here or not. But... I see you have 2 different supports, a hinge and a roller. The hinge has 2 reactions (x,y) and the roller only has 1 (y). So I assume the support is irrelevant?

[@austinfrazier6589]

There is no force on the x axis, so we know that the X for the pin would be = 0

[@wakeupthisisntreal8168]

Good question! I have no clue! I hope you figured this out though! And also chicken is very tasty.

[@JacksonTimms-c8x]

Thankyou this was amazing help

[@tantwoo3865]

I finally found out which members are zero force in my example, I struggle with finding them... Zero force members are simply forces that has no reaction to equate the joint to zero force in any direction.

[@vijaymerson4070]

Sir I have a doubt. KL and KJ are colinear and why they have different and opposite loads. Please.

[@KID4271]

How did he solve for KJ and KD when both equations had 2 unknowns?

[@hillaryotabor5082]

Simultaneous linear equations although u would've prolly known by now

[@kerchin6573]

jd has 20 kn downward, shouldnt it be included? @19:50

[@pejhonsetareh4723]

That's I was thinking. Let me know if you figured it out why not? My exam is tomorrow 😬

[@zunaidhassan9662]

If I understand it, 20kN is not acting on joint J but on joint D so it's not considered there.

[@abdulselamabdurahman1875]

lifesaver 👍👍👍👍👍👍👍 . long live

[@Ael_BeatzGlobal]

we're gonna be here forever🤣🤣🤣🤣🤣, I almost died

[@sahildin7396]

If A is a pinned joint, why does it only have a reaction force in the vertical axis and not both horizontal and vertical axis

[@jdorozco90]

Because there are no applied forces that have an X component to them, so he found the Reaction at A in the X to also be zero (There's nothing to react to).

[@CastroDanielFIII]

May i ask sir, Why didnt you used joint D instead of J?

[@rbertcarrou4462]

Can I get a PDF past questions for the mechanic mathematics..?

[@muhammadaimanbinzakaria2584]

hyee. sorry, but may i ask is there no reaction force (ax) at joint a ? why is that ?