Moment of a Force | Mechanics Statics | (Learn to solve any question)
Vložit
- čas přidán 6. 08. 2024
- Learn about moments or torque, how to find it when a force is applied at a point, 3D problems and more with animated examples. We talk about the line of action, breaking forces into components and using that to find moments, and resultant moments. We also go into using the cross product to figure out the moment as well.
🔹Breaking 2D forces into components: • Vector Addition of Cop...
🔹Forces Along a Line (3D forces): • Force Vectors Along a ...
🔹Finding the Cross product: • How to Solve a Scalar ...
If you found these videos helpful and you would like to support the channel, please kindly see the following links:
🔸Patreon: / questionsolutions
🔹 ko-fi.com/questionsolutions
🔹 www.questionsolutions.com/don...
🔹 PayPal: questionsolutions@questionsolutions.com
Intro(00:00)
Determine the moment of each of the three forces about point A. (02:24)
The 70-N force acts on the end of the pipe at B. (04:30)
The curved rod lies in the x-y plane and has a radius of 3 m. (05:25)
Determine the moment of this force about point A. (06:28)
Determine the resultant moment produced by forces (06:58)
Find more at www.questionsolutions.com
Book used: R. C. Hibbeler and K. B. Yap, Engineering Mechanics Statics.
Hoboken: Pearson, 2017.
⭐⭐If you'd like to see more examples covered and at the same time support the channel, please see: czcams.com/video/nPvG1bYFbko/video.html ⭐⭐
🔹Clockwise moments positive, or counter-clockwise positive? czcams.com/users/shortsP029mqnp4XY
🔹Please note there is a typo at 6:23. The "k" term is negative, not positive, so it's {-128.34i + 128.34j - 256.68k}
🔹At 6:31, there is a typo in the question, we are finding the moment about point B, NOT A. This is a typo in the question only, all steps are correct.
🔹When to use sine or cosine: czcams.com/users/shortsvynnKlJD_Jo
Hi sorry for bothering. For the j term in the same timestamp you've provided, I can't seem to get positive j.
4(-42.78)-(-2)(21.39) = -128.34
btw thank you so much for these videos. Its really helping me a lot you have no idea how thankful I am to have found this channel.
@@moonbunnies5216 Since this is the second multiplication, it will have a negative in front first, so it will be like this: -[4(-42.78)-(-2)(21.39)]. You can always double check using this website: onlinemschool.com/math/assistance/vector/multiply1/ . Simply plug in the 2 vectors.
And you are very welcome, glad to hear these videos are helping :)
@@QuestionSolutions oh my god I totally forgot about the formula for that, should've checked myself before commenting, thank you so so soo much for letting me know.
@@moonbunnies5216 Happens to everyone I think :) Best wishes on your studies!
Completing my Engineering from CZcams University of Engineering and Technology
Best wishes with your studies!
For realll😂😂😂😂❤
Best CZcams professor😊 thanks a lot
Same condition same place 😂
Which engineering program?
well I'm obviously subscribing. I have been struggling with this topic for a while and your video just helped me get it. 1 step closer to becoming an engineer thank you : )
That's really awesome and I am super glad you got it :) Thank you so much and I wish you the best on your journey to become an awesome engineer!
Same here✨
@@QuestionSolutions
Awesome. Thanks dude. 👌🏾
@@QuestionSolutions Very Smart
Thank gosh I found you! I was struggling so much with moments and now I know it's the PERPENDICULAR distance. Thank you so much :)
Haha, yes, perpendicular distance :) Glad to hear this helped!
Your honestly one of two best tutoring channels for physics in all of YT. Continue making quality vids bro!! (also new sub)
Thank you so much for your kind words! Really nice of you :) I will do my best to continue the channel.
You deserve my subscribe! I hope all students trying to learn this lesson would see this video. Thanks for the tutorial. Keep it up.
Thank you very much! :)
I am here just for the recap since most of the engineering lessons I took required this procedure to solve problems. Thank you! You discussed better than my college instructor. Specific and concise!!!
I try my best to make them as concise as possible :) Best wishes with your finals!
Awesome, so helpful. I was having trouble with this topic, watched the video, worked some practice stuff out on paper and cruised through the rest of my homework on this subject. Thank you!!
You're very welcome. You're doing exactly what I hoped students would do :)
Thank you so much you've saved me, in just minutes you managed to explain better than hours of lectures!
I am really glad to hear that :) Best wishes with your studies!
Same bruh, my professors can't teach shit
Coming from a class with a curriculum that doesn't follow the book to the T, this is such a great way to get study/example problems. THANK YOU SO MUCH!!!!
You are very welcome! I hope you gain a firm grasp of the materials and do amazingly on your exams!
you explained the whole topic and worked all possible types of problems related to this topic in just 8mins! you're amazing!
Thank you very much!
You are doing god's work my man, bless your soul holyyyyyy, Keep doing what you're doing man
Many thanks! I wish you the best on your studies.
Excellent explanation. Thank you very much. Very well explained. The best part is explaining the solution really fast and also clearly.
Thank you so much for your nice comment. I really appreciate it.
tysmmmm I've been trying to figure this out on my own for an hour now and you just made it all clear now
I'm definitely going to like and subscribe
Thank you so much, really glad to hear it was helpful! Keep up the awesome work.
I cant be thankful enough to came across ur vids!! definitely helps me to understand it like whatttt soo much better than my actual lecture. And the fact u r replying to all the comments is amazing and i get to learnt from others comments too! great job really, keep doing what u r doingg thank u veryy muchhhh
Thank you for your kind comment and I am very happy to hear that these videos help. Keep up the awesome job and I wish you the best with your studies! :)
@@QuestionSolutions Will do my best and thank youu for the wishh!!!
@@ummiaisyah7560 You're very welcome!
BIG UP MY MAN QUESTION SOLUTIONS!! Thank you for putting these together!
Many thanks!! 👍👍
Thnx so much for explaining it! I had mix feelings about this topic since my professor went over it fast
I hope it was helpful to you. Best wishes with your studies!
May God bless you, your family, and your knowledge that you spread. You have made me understand, so I ask God Almighty to increase you and bless the goodness in you and increase you. Syria🇸🇾🥇
Wow, thank you very much, that was a really nice comment. I wish you the best in your studies and all your future endeavors!
You made this subject come out so easy, thank you! I'ma go pass a test!
Awesome! Give it your all and I wish you the best on your test!
Damn man im really happy i found your channel man💓💓 i read a lot of book but its kind of confusing. While you explain it very simple. Thank you man I already shared your videos to my classmates since it is very helpful💓
Thank you so much 💓 I really appreciate your comment and the shares, super nice of you! 💓💓💓💓
thanks for the awesome explanation methods you just made the subject extremely easier
I am really glad to hear that! Best wishes with your studies.
I have been struggling with this chapter in Applied Mathematics, Thank you very much, now i trust myself fully in Moments, i also subscribed to your channel and sent the link to my fellow varsity mates
I am really happy to hear that and I really appreciate your subscription and the share. Means a lot and I wish you the absolute best with your future studies! Keep up the good work 👍
Well, I am subscribing, your precise and clear, exactly what I have been looking for.
Thank you very much! :)
Thank you! Been sitting in class not understands a thing and saw this video and now i get it.
Glad it helped! Best wishes with your studies.
Gorgeous explanation, thank you!
You're very welcome!
Thank you so much, Great Video! it was very helpful for my statics exam!
I am very glad to hear that :) I hope you did well on your exam.
Your videos are so amazing, thank you!
Thank you for your kind comment! I hope they are very helpful to you.
Thank you. I think I get it now. I’ve been stressing and struggling summation of forces and moments. I think I finally got the principle. It’s just that the figure is overwhelming me but I think I’m almost at it now. I’m definitely subscribing ❤
Thank you very much. I am sure you will get it, just practice a few problems and follow along the examples :) I wish you the absolute best with your studies!
i love the way of ur teaching where u focus on concept
Glad to hear :) Best wishes with your studies!
Great explainations 👏, hope for more videos 👍
Awesome :) Thank you so much! 👍👍👍👍
You ara amazing man. I loved it. I was struggling but now i know what to do
I am glad to hear that! Keep up the good work.
5x faster than my prof.
👍😁
And its easier to understand 😃😂
5x better
honestly, my professor makes this stuff seem like rocket science with how bad he is at teaching it
been lost for so long dropped the class once already and watched this video and now everything makes sense
I’m really glad to hear that the video was helpful for you! It’s not uncommon to feel lost when learning something new, and it’s great that you didn’t give up. Do you best, keep going, you’re doing great! 😊
Dude, just... Thank you so much, you don't know how much you saved me, Thank you.
You're very welcome! Keep up the great work, best wishes with your studies.
It is soooooo helpful! Thank you!!!!
You're very welcome!
Great examples, thanks!
Glad it was helpful!
Crystal clear explanation
Many thanks!
I really enjoyed it, thanks
Glad to hear :) You're very welcome!
Clear explanation, thanks
You're very welcome!
Perfect explanation!
Thank you very much!
absolutely fantastic 👏👏
Thank you :)
dudee you're such a legend!!!
Thank you :)
You earned my subscription 👍
Thank you very much, I really appreciate it. 👍
thank you so much brother
You are most welcome.
Thx for your great effort!
In the last problem, If we wanted to use position vector OA, what force should we use when doing the cross product?
The forces remain the same, only the position vector changes. So when doing the cross product, you would use rOA. 👍
great content..keep it up
Thank you very much!
tyssm u ddont know how much youve helped me for this
You're very welcome! Keep up the great work and best wishes with your studies.
Praying Tanaka has a suggestion: may you include sample problems where we are given angles and not just lengths? It would be very helpful
🌝
🙏
I am not sure I understand what you mean? You need distances to calculate a moment, or you use the angles given to figure out the distances first. Could you elaborate on what you would like to see? :)
You are my hero. Thank you
Many thanks!
Wow, you are a lifesaver
Glad to hear!
thank you so much, u r a holly person!
You're very welcome!
The best video on CZcams, nothing better than this but could have been the best video in the galaxy if video was a bit slow.
Edit: by bit slow i mean 10x slower
Thank you for your feedback. :)
Thank you so much.
You're very welcome!
This is soo good
Thank you very much! I hope it was helpful.
Thank you so much :D !!
You're very welcome!
Wow, Even after graduating. I still remember how to do it. Just needed to refresh my memory a little.
Congrats on graduating and well done for remembering!
amazing!
Thank you!
I love this man
❤
Thank you so much ❤
You're welcome 😊
Great video! Really helped me wrap my head around this. With the curved rod question, wouldnt the k-value of the cross-product be -256.68k? ((4 x -64.17)-(0x21.39)=-256.68k) Otherwise it wouldnt be perpendicular to the plane created by the two vectors.
Glad to hear it was helpful. :) And yes, I have a pinned comment with the typo corrected. 👍
Thanks Man👍
You're very welcome! 👍👍
amazing helpful
Thank you very much!
God bless you man whoever you are
Thank you very much! Best wishes with your studies.
This is the best video
Thank you very much!
please i'd like to ask if the position vector could be from anywhere like Rac instead of Roc
Please kindly provide a timestamp to the place you're referring to.
Your videos are great!! Would you please be able to do a video on torsion as well as equations of elastic curves (deflection/ flexure formula)?
Thank you very much and I will definitely add it to my list of videos to make :)
@@QuestionSolutions Thank you!
Amazing
Thank you! Cheers!
for the fourth example, why are you using the position vector for BC if you're taking the moment about point A? would you not use AC?
There is a typo in the question, the moment was suppose to be about point B. I wrote a pinned comment about this too because I get asked it so many times. 😅
THANK YOU
You're very welcome!
You Deserve a Globe's Best Teacher Award 🤩
🤩 You're too kind!
Yes,he indeed deserves it.
God bless u.....
@@freakingik2781 :)
in 6:13 , I used the position vector OA. Why the direction of Z axis of my moment is -256.62 and not 256.2. Is it wrong?
It should be negative. Please show me the position vector you got. Thanks!
Sir,here is the moment when I use the position vector OA.
Mo={ -128i + 128.34j - 256.68k }
rOA= { 3i +3j +0k }
So if there's not any mistake the Moment must be the same for both position vector rOA and rOC. isn't sir
Thanks a lot for ur help 😊😊
For example 3, if r is the position vector from the point where we take the moment about to any point along the line of action of the force, can r be the position vector from O to A? if I do that i get -128.4i +128.4j -256.08k? (the only difference is the sign of the z component to your answer).
You absolutely can. I have a typo in my answer (see pinned comment). Your answer is correct.
@@QuestionSolutions ohh thank u
Thanks for your help in this topic was wondering that isn't turning clockwise should be negative?
You can pick either direction, it makes no difference as long as you follow through with your positive and negative signs.
So for example, assume you picked counterclockwise to be positive, then if you get a negative answer, the moment is clockwise. If you picked clockwise to be positive and you got a negative answer, then the moment is counterclockwise. If you picked counterclockwise to be positive and you got a positive answer, then the moment is counterclockwise. Lastly, if you picked clockwise to be positive and your answer is positive, then it is clockwise.
@@QuestionSolutions Thank you
the BEST☺
Thank you :)
Sir at 2:45,when finding the components of x and y for F1,why did you use sin for the x-component instead of cos and cos for the y-component instead of sin?
Or am I mistaking please?
Please watch this: czcams.com/users/shortsvynnKlJD_Jo?feature=share
It'll clear up all your doubts. :)
Thanks teacher
You're very welcome!
Hello, I have a little mental hurdle that I'm trying to overcome which is represented at 3:58 does the line of action change, and does it become parallel to the black line representing the support at point A?
I assume we are talking about the 400 N force? If so, the line of action is always with respect to the force. So if we extend the orange dashed line backwards and forwards, that is the line of action. If that line crosses point A, then it can't create a moment. Here, that line of action is 5 m away from point A.
thank you
You're very welcome!
At 4:25 it was mentioned clockwise was positive, while I’m aware that counterclockwise is positive while clockwise negative, could you explain? as I’m confused now 😢
You can use whatever way you want to be positive. If you like counter-clockwise to be positive, you can solve it that way. Regardless, you will end up with the exact same answer. :)
I love you as a teacher
Thank you very much! :)
Look at this legend
:) Many thanks!
Hello,
I think there is a mistake at 6:23, Roc should be Roa since the starting point of the force is A no ? Or maybe I don't know the rule well ^^
Edit : Well I just heard "position vector from point O to any point of the line of force action", I learned that thank you :)
Yes, as long as the vector goes to any point on the line of action of the force, you will get the same answer 👍
I got -128.34i +128.34j -256.68k for the cross product in 6:24.
You are right, there is a typo, the k term should be negative. 👍
Top G lesson
Many thanks! 👍
At 2:41 Why did you use the horizontal component of F2 for F2x instead of the vertical component like in F1?
Okay, so I think what you're actually asking is, why did I use cos for F2x, but use sin for F1x, and you are assuming cos and sin are related to horizontal and vertical components. If this is your question, please erase that thought out of your head. Sin and cos are NOT related x/y/horizontal/vertical components. They are purely based on the angle and it's corresponding side. I have no idea where students get this notion from, but please make sure you don't think like this. 😅I really encourage you to look at this video (czcams.com/video/NrL5d-2CabQ/video.html), it's not long, and if you're really tight on time, just watch the first example. It will give a very good foundation for working with sin/cos and how to properly use them. I break it down step by step and by the end you will never get confused again but sin and cos.
If this isn't what you're asking, I am not too sure I understand your question. Maybe rephrasing it might help me, if so, I am sorry :(
Can you please explain where the line of action is in the flagpole example? I'm assuming the line of action is up and down the flagpole
Your assumption is correct. If we have a force directly along the flagpole, there would be no moment created.
i like your videos it helps me a lot in my engr course. can i ask? how did you get the cross product from the 3 example
when i cross product i get the 128.34-213.9-256.68 is not the same from what you get
Please see: czcams.com/video/F8IHrg3pc7g/video.html
Hi, I have a question, why in 5:45 we get the position vector from OC and in 6:41 its from BC? That wouldn't mean that our position vector in 5:45 should be from O to A? I have tried that and it will change the values of the momentum vector
You can take it from O to A, and you will get the same answer. There will be no difference. You most likely wrote down an incorrect position vector. The position vector OA would be 3i+3j+0k. Keep in mind that there is already typo in the solution for that question as mentioned in the pinned comment. The answer for that problem is -128.34i+128.34j-256.68k. Whether you use a position vector from O to C or O to A, you will get the same answer.
@@QuestionSolutions Oooh, I just checked, and you are right! I was messing up with the position vector, but yeah, when you do it with 3i+3j+0k, you get the same answer. Sorry for the confusion. Thank you for your help and answering my comment, even though this video is 3 years old! New subscriber
@@ThunderGowPlayer You're very welcome. I am glad you got it :) Keep up the great work and best wishes with your studies.
For the last problem, why do we have to add the momentum of the two forces, if they are operating in opposite directions on the same tower?
The word "resultant" indicates that whatever you find, whether it's separate forces, moments, etc., must be added together. It's really just showing a single moment instead of 2. Another way to think about it, is to realize that the resultant shows the result of multiple forces/moments acting at a singular point.
A uniform metre scale of mass 200 g carries of a block of mass 800g at one of its end .At what distance from the same in end does does a knife and balance the scale?
Sorry, I don't solve questions like this because then I have to solve everyone's problems 😅 I encourage you to use math/physics forums if you need help with a specific question.
For the first question, when solving the moment for M3: Shouldn't it be -300n(5m)+400N(4)?
So remember, we are looking for the perpendicular distance. F_x is horizontal, so we are looking for the vertical distance from point A, that's the perpendicular distance, which is 4m. F_y is vertical, so we are looking for the horizontal distance from point A and that's 5m.
6:23 shouldn't be 256.68 a negative (-)? Since we alternate our operations in doing matrices + - +
last term should be + [(4)(-64.17) - (0)(21.39)] which results to - 256.68.
Please correct me if I'm wrong.
Please see pinned comment. You are correct, it's a typo. 👍
@@QuestionSolutions Thank you!
Hi, I love you thanks for this.
You're welcome! 👍
Isn't F1x be equal to cos(theta)? since cosine represents the x-axis while sine represents the y-axis?
Please, take 1 minute and watch this video: czcams.com/users/shortsvynnKlJD_Jo
That is incorrect, and you must erase that thought from your mind. You will lose so many marks on your exams from that view point, and I have no idea where students got this idea from.
u r a boss.
😅
Hi, i thought clockwise direction was negative and counterclockwise was positive or it doesn't matter?
See pinned comment.
just subscribed
Thank you very much!
@ 7:50 I think the j in MOB is - 0j since the j should be negative (not that it matters since the value is still 0)
I don't assign negatives to zeros. It's neither positive or negative, it's just zero because -0=0 also, to me, positive "looks" nicer 😅
Was studying these same things for four hours and didn't understand a single thing. Can't believe I just understood everything in 8minutes😂😂I appreciate 🙏
I am really happy to hear that! Well done and keep up the awesome work :)
at 4:53 why isnt the fx+0 because its along the line of action pf the force plus how are you able to tell if the fx is clockwise or anticlockwise
It's not along the line of action. You need to look at it with respect tot he point where we are calculating the moment. In this case, it's about point A. You can tell if it's clockwise or counter-clockwise by imagining the piece rotate around point A. It's easier to visualize if you cut out a piece of cardboard, pin it at A, and then push with your fingers. See how it rotates and then you will get a feel for it.