Less Simple Pulley, Part A - Engineering Dynamics Notes & Problems

You'll find more dynamics problems at:
www.spumone.org...
Here is a problem where the pulley kinematics are not trivial. I demonstrate a recipe for working it out.

[@JQuint_]

After 7 years, this explanation is still superb. Cheers!

[@maxisjaisi400]

I'm a high school student from Malaysia. You seem to have a natural knack in teaching Physics. Your tone is not monotonous, I could watch the entire video without losing interest. And your explanations are very detailed, you do not pull figures out of thin air. You analyse them in detail. Keep making videos and thank you!

[@altuber99_athlete]

This channel is a hidden gem.

[@harmeetsokhi]

The part after 7 mins... The finest and simplest explanation I have ever come across for pulley problems....

[@elthechieftain]

Now, You teach the exact same way I teach, detailed, and that makes the concept not only stick better but you'll learn even better yourself:) Thanks

[@dominiqueengome5069]

Thank you sooo much! This makes so much more sense than when I did it in class. It's a lot more detailed than what my professor did and now I can actually understand what he did! Thanks

[@rajsondhi6912]

a round of applause for you man, thank you so much

[@MrDamours]

Ty! The rope movement explanation is very clear and helped me understand pulley systems!

[@ADGPEN]

Heya im glad i found your video, the problem is nearly identical to what I need help with, (mine has different masses). Also, you scared me because the end was coming up and I had no idea what you were going to have to do to solve for acceleration... Thanks for the video

[@venugopals9680]

Great 👍 explanation. That change of rope segments explanation is ultimate. Thank you. 😊☺️

[@Neo4real]

thanks...this helps during a last minute all nighter..

[@toe39]

I love how you draw the straight lines

[@kingvkronaldo.9273]

Excellent explanation.. especially the acceleration relationship was elaborated well

[@bdcoller]

Glad it helped.

[@MoonLight11023]

Thank you so much man. You are really an excellent teacher. Hats off to you Boss.

[@bdcoller]

You're welcome.

[@87VNP]

Much wow....thank you so much.

[@mwont]

Awesome. Thank you so much for your help

[@apeirostudio2993]

You are a life savor bro

[@bdcoller]

Glad to help

[@jlpsinde]

Thank you, it's perfect at all levels! A great help, incredible awesome video!

[@bdcoller]

You're welcome.

[@tsoojbaterdeneharvard3187]

Thank you so much.God bless you🙏🙏🙏

[@bahadorrousta6106]

thank you

[@dk7aditya]

Good Explanation bro, Keep it up

[@nitotech]

Dude your awesome! The constraint problem was annoying me.

[@anushreedey5448]

thanks.it's really helpful...........

[@Allthingstech3108]

Lovely

[@1993yaghi]

Great, thank you!

[@ISLAMguidanceful]

quick question, on block number 1 there is a rope hanging from the pulley holding the block why dont you take that into account as well?

[@bdcoller]

+Hussein Elsherbini In my free body diagram of that block, I included the pulley and the rope connecting the pulley to the block. Therefore, the rope connecting the pulley and the block are INTERNAL. When you write equations for Newton's laws applied to a system, one only includes EXTERNAL forces.

[@ISLAMguidanceful]

in this case how do i come to recognize if i should include the whole pulley and the box or just the box. thanks for the response :)

[@bdcoller]

+Hussein Elsherbini You can do it either way. But if you only include the block in the free body diagram, then you will have to draw a separate free body diagram for the pulley and write equations for it.

[@noreaction1]

What if the fixed plane where the rope and top pully are attached is at an angle and not perpendicular to the mass? How does that change the tensions?

[@bdcoller]

I have a video of a more complicated pulley problem for which the blocks are on slopes. You can find it here: kzbin.info/www/bejne/boGVlolqYthsd6s

[@hamzamisk1570]

thank you so much but what's the name of the app you use in this video plz :D

[@bdcoller]

For that video, I used a program called Smooth Draw. Now I'm using Autodesk Sketchbook Pro.

[@hamzamisk1570]

Thank you so much :-*

[@WonderingNobody]

Could you please tell me how I wold calculate the Kinematic relation if the length of S2 is not equal to S1?I mean both pulleys are closer to each other?

[@bdcoller]

+I Wonder : It's the same. There is no assumption that s1 and s2 are the same or similar.

[@WonderingNobody]

Thanks but I am having hard time to understand the 2:1 relation Between S1 and S2.If The part of the rope after C2 is not equal to S1 then we can not write 2S1 in the length equation.I have the same problem in my Mechanics exercise .But In that case two pulleys are closer to each other.

[@karimkhan1312]

extra ordinary very good

[@cimmy333]

thx

[@bdcoller]

wlcm

[@Utshaw]

Can anybody explain me why a1 is not equal to -a2 here??

[@bdcoller]

It's because of the pulley kinematics. When block 2 moves 1 meter, block 2 moves 0.5 meter in the opposite direction. Likewise, there -2:1 ratio of velocities and accelerations.

[@dk7aditya]

Also There are Two Strings,look carefully