The motor at C pulls in the cable with an acceleration... Find more at www.questionsolutions.com Book used: R. C. Hibbeler and K. B. Yap, Mechanics for engineers - dynamics. Singapore: Pearson Education, 2014.
Пікірлер: 41
@nayrahalhelo63234 жыл бұрын
Actually this was short and straight to the point 👏🏻thank you...
@QuestionSolutions4 жыл бұрын
Glad to hear! You're welcome and good luck with your studies!
@syabongajele64313 жыл бұрын
lately your channel is my habitat Sir
@QuestionSolutions3 жыл бұрын
❤ Glad you enjoy it :)
@ahmadaloufi40672 ай бұрын
Are you Sadio Mane?
@user-gu8pe3ol7g Жыл бұрын
The acceleration of B is actually going to the left so why we didn’t consider it as a negative?? Ba=-5t So S = -2.5t^2 So 0.125t^4-2.5t^2=3
@QuestionSolutions Жыл бұрын
Once you draw your position coordinates, that direction, (regardless of the movement of blocks), will be considered positive. At the end, if you end up with a negative answer, then it's opposite to the direction of your position coordinates.
@darrylcarter36913 жыл бұрын
The way I would see left as being positive and right being negative is looking at the rope attached to Block A. Notice how the length is decreasing.
@QuestionSolutions3 жыл бұрын
👍
@darrylcarter36913 жыл бұрын
@@QuestionSolutions thank you man. you’re the best.
@QuestionSolutions3 жыл бұрын
@@darrylcarter3691 Thank you :)
@sarahkamal25854 жыл бұрын
This was very useful. thank you!
@QuestionSolutions4 жыл бұрын
I am really glad to hear that. Best of luck with your studies!
@Aurora-pp3cs4 жыл бұрын
Why Sa+Sb= 3m? Wouldn't it be 6m since the position of both blocks was displaced from 3m to 0m, which means each of the blocks was displaced by 3m, and that will make a total of ( Sa+Sb)=3+3= 6m I am confused about this part. Please clarify. Thank you!!
@QuestionSolutions4 жыл бұрын
The question is only asking us to calculate the time needed for the blocks to be apart 3 m from each other. Another way to think is that they start from d = 3 m, and we need to find when d = 0 m. Hope that helps.
@simeonserafimov48232 жыл бұрын
@@QuestionSolutions can you clarify a bit more please? How do I think about this? Is it the fact that the sum of the two that needs to equal three which means that B will make a displacement to the right and A to the left SIMULTANEOUSLY until B will be at the end of A (from the left) so that d=0? Thanks in Advance!
@QuestionSolutions2 жыл бұрын
@@simeonserafimov4823 That is correct. It's a weirdly worded question, but it is simultaneous movement. So the movement of both blocks (3 m in total), gives us the d = 0 we are looking for. I think students get confused thinking its 6 m, but the datums are opposing, so it becomes simultaneous movement. I think a good way of seeing this is to use a ruler and 2 erasers and push with your fingers to get an intuition for what this question is asking. :)
@NAYAN-t3e8 ай бұрын
@@QuestionSolutionsFollowing from sign convention of C side, As B moves to the Left, simultaneously A moves to right, both are starts from rest at t = 0. From given, d = 3 m at t = 0. Then, for d = 0 then, B should move by that distance d = 3 on left side, relative to A at that particular instant. Hence, relative displacement of B with respect to A, S_B/A = S_B - S_A in vector form, + d = + S_B - (-S_A ) As from C side (i.e. convention) Displacement of A at any instant is in right (i.e. - ve) while, displacement of B is in left direction ( i.e. + ve) as the motor D draws in B in left direct. So from C side convention it is in left & correspondingly d is displacement of B w.r.t. A at any instant, Means it covers d = 3 m from right to left in +ve direction, As the language of problem says when d becomes zero means it should move from d = 3 (on right side) to d = 0 towards left. So, + d = + S_B - (-S_A) becomes, + d = S_B + S_A As you given the step. Is my approach correct ? Or else any mistake in my approach, please suggest it asap. I will be thankful.
@williamrotty56913 жыл бұрын
Hi, what is the point C for which u gave the distance Sc? is it an just an arbitrary point between the motor and block A?
@QuestionSolutions3 жыл бұрын
Yes, that's right. We need that to show the movement of the cable.
@yveskourieh2 жыл бұрын
thanks!!!😊
@QuestionSolutions2 жыл бұрын
You're welcome :)
@enrikvantichelen82433 жыл бұрын
So you just drop the constant after integration?
@QuestionSolutions3 жыл бұрын
Please take 8 minutes to watch this video: kzbin.info/www/bejne/f6bHgYN9frtoh68 I think it'll help a lot and clear up a lot of questions.
@rastonick5891 Жыл бұрын
im confused to why its 2Aa+Ac
@QuestionSolutions Жыл бұрын
Sorry, where are you referring to?
@Kimi-vn7jz4 жыл бұрын
Why must we take the aA as positive value before integrate?
@QuestionSolutions4 жыл бұрын
You don't have to really do that, but I just find it a lot easier to work with positive values, that way, you don't have to keep writing arrows to the left. At the end, you will still have to make it positive to get the displacement. So why not just do it at the start and then you don't have to worry about it. At least that's what I do when I solve questions. I hope that makes sense, but you can do it the way you mentioned too and then switch signs at the end. Entirely up to you.
@Kimi-vn7jz4 жыл бұрын
Question Solutions but still why do I have to change it to positive value? What if I plug in - 0.125t^4+2.5t^2=3. Would it be wrong?
@QuestionSolutions4 жыл бұрын
@@Kimi-vn7jz Good question. Yes, that is wrong. You are now using two different references to find the answer. If you use that reference (sa = -0.125t) as negative, then from that reference, you will get -2.5t for sb, and -3 m as the distance between them. I am not 100% sure how to explain this clearly, I think when you do a lot of questions, it will probably click in your mind. Change it to positive, and all should be good. I think the text book states the values need to be written so that it "has a positive sense."
@Kimi-vn7jz4 жыл бұрын
Question Solutions okay thanks a lot! This is only applies for pulley right?
@QuestionSolutions4 жыл бұрын
@@Kimi-vn7jz You're very welcome. And yes, for pulleys, a positive sense is used.
@lucasvanhove5032 Жыл бұрын
thx
@QuestionSolutions Жыл бұрын
You're welcome.
@ElCrankoPunko3 жыл бұрын
can you pls explain how Sa + Sb = 3 ?
@QuestionSolutions3 жыл бұрын
Please watch this video first: kzbin.info/www/bejne/f6bHgYN9frtoh68
@ElCrankoPunko3 жыл бұрын
@@QuestionSolutions saw that still have doubt
@QuestionSolutions3 жыл бұрын
@@ElCrankoPunko So what we're trying to do is calculate the time needed for the blocks to be apart 3 m from each other. Another way to think is that they start from d = 3 m, and we need to find when d = 0 m. So we can say the length SA plus the length SB has to be 3 m. This 3 m is the difference. I hope that makes sense.
@ElCrankoPunko3 жыл бұрын
@@QuestionSolutions Is it like Sa-(-Sb) = 3
@QuestionSolutions3 жыл бұрын
@@ElCrankoPunko It's the difference between the lengths, so you can think of it the way you're thinking.