Mechanical Engineering: Particle Equilibrium (13 of 19) Pulleys and Mechanical Advantage

[@NishantGogna]

For those wondering why the ceiling requires 125N to hold a 100N block, the extra 25N are coming from YOUR force on pulling on the rope, which is 25N.

[@sanskartiwari2996]

thanks bro that was just what I was thinking

[@GeertDelmulle]

Nishant Gogna, yep, and that is yet another free body diagram you can draw (around the whole lot).

[@petethewrist]

@@GeertDelmulle Yes indeed,, if you do that around the whole lot of the centra pull system with wheel on top left fixed in position say with a pin the three top ropes would show 100 n surely and any pull force then applied to the left down rope would be lost or sheared by the opposite rope and so on, the force the ceiling see at any time can only be the 100n plus the weight of the pully system.. lke to see this done in real time with spring scales on top three ropes may be?

[@bobu5213]

Ah nice thanks man

[@raynic1173]

@@petethewrist Do it, go buy some fish scales and video!

[@GloCas300]

Best explanation I found on KZbin. Huge thank you

[@abelgirma477]

True

[@MamoonBakeer]

After searching tens of videos; this is the best simplified video about pulleys. Thank you for the art of delivering pure information.

[@giant3909]

This is the explanation I was looking for and it is hands down the best one I ever found

[@karthiknagendran9474]

these sessions are really good, i have been trying to learn these kinda questions for the past few months for my JEE preparation and i couldnt learn till date, and finally your explanation was really easy that i could understand! thanks a lot professor!

[@MichelvanBiezen]

You are welcome. Good luck on your JEE test

[@ajs18s86]

Counting the lines that are also getting shorter tells you what mechanical advantage you have. Great video.

[@soupcanpyro9421]

This man taught me something that i struggled with since middle school Thank you michel

[@MichelvanBiezen]

You are welcome. Once you see the technique, it removes the mystery. 🙂

[@sunkarasudha4861]

His way of dressing itself shows what kinda gentle man and a good professor he is.....huge respect for him

[@petereziagor4604]

You're an amazing teacher. I decided to solve these problems before watching, I got all correct. Didn't even take up to a minute to visualise them

[@MichelvanBiezen]

Good job. 🙂

[@petereziagor4604]

@@MichelvanBiezen thank you

[@ridermak4111]

Stationary (anchor) pulleys only redirect force. Moving pulleys (load) provide the mechanical advantage. Yeah, I know, that’s what he just showed us. Anchored or moving just helps my brain quickly calculate a system that I’m looking at. That third example on the white board is a fictional mutant. What I mean is, I don’t think you’ll see it in any practical application. Let me know if I’m wrong. There is a video of a small vehicle pulling a tree out of the ground with a 45 to 1 pulley system. And if you have a long length of strong rope but no pulleys, KZbin search “flip flop winch”. It’s amazing.

[@internetrules8522]

Example 1 prediction: 50 of the weight has to be going directly into the cieling at the beginning because of the ceiling rope, so the other 50 weight has to be going into the middle pulley. 25n of the middle pulley has to be going into the ceiling from the rope, so 25n has to be going into the top pulley. The top pulley just redirects our force instead of multiplying it, so we need to put in 25n of force for 4x mechanical advantage and 125n in the ceiling. 100 from the weight 25 from our downforce. Ok I seemed to visualize the free body diagrams similarly to you thats good. I didn't consciously think of it as 2 separate ones, but that seems to be the process I used atleast. Example 2 prediction: has to be 50 weight on each connected pulley. Bottom Right pulley has to have 25n going to the cieling rope, and 25n going to the Top Right pulley. Bottom Left pulley has to have 25n going into Top Right pulley, and 25n going into Top Left pulley, and top left pulley should also have 25n from our pulling. So 25 at right ceiling connection, 50 at middle ceiling connection, 50 at left ceiling connection (25n from weight and 25n from our pulling). OH 3:02 was really important to hear. I was kind of confused about how we as the puller add more downforce, but both sides needing equal tension i think helps me make sense of it. I again didn't visualize the FBD like how you drew it, but I think i still did a similair process Example 3 prediction: Bottom pulley has 3 connections, the Top Left pulley has 2 of those connections, so it has to be 66n, Top Right pulley has 1 of those connections so it has to be 33n, and because both sides need the same tension we need to be applying a downforce of 33n. So 66n on each pulley for 132n on the ceiling. Ok I think I managed to predict all of those. Your explanations are really helpful.

[@MichelvanBiezen]

These can be tricky. Hopefully after a few examples it became clear. 🙂

[@ndiinekelatangivatilifa7412]

Best explanation ever Mr Michel.......finally i got pulleys ..

[@semanavidi8694]

Excellent demonstration of the pulley system, you must be an engineering professor, thank you.

[@ptyptypty3]

Hi Michel .. before I saw these Pulley Videos.. I would have thought that the Total Weight being supported by the CEILING would always equal the Weight of the mass being supported.. WOW, was I wrong.... Thanks for another Counter Intuitive moment in Physics! I then imagine just ONE pulley hanging from the Ceiling with one rope over it. One end of the rope was connected to the 100 lb Mass and the other end of the rope went over the pulley and was being held by ME.. So, I would be pulling with 100 lbs of force to hold the 100 lb Mass steady. Therefore.. the ceiling would be pulling up with a 200 lbs Force !!! amazing!! thanks again for your nonstop contribution to the perpetuation of Knowledge to the Masses.... not kilograms, but People :)

[@MichelvanBiezen]

Philip. Good insight. It is interesting where the principles of physics will take you.

[@observer236.chitrakoot7]

we require teacher like you to teach us physics

[@tomko5055]

Needed video like this, thanks.

[@fightforfitness2256]

A giant thanks from me for the wonderful explanation .

[@inquisitive.lurker]

There was a similar problem like this on our first Statics exam. I was completely unprepared for it 😢. even though it's a relatively simple problem and I've taken physics before. The only given in the entire problem was a single hanging weight.

[@willet2275]

Your channel, sir, is my discovery today. Treasure;)

[@MichelvanBiezen]

There are 7900 videos on this channel. Enjoy!

[@rhoddryice5412]

@@MichelvanBiezen What else to do on Christmas?

[@tothemaximilian]

Finally a clear understanding of this! Thank you!

[@andrerouth4253]

Hi Michel, thank you for that very clear exposition. I have a question about how far the load can be moved before the upward moving pulleys can move before banging into the fixed pulleys. #1 looks like a winner in the MA = 4 category because it only uses 3 pulleys compared to #2. #3 has an MA of only 3 but uses the same number of pulleys as #1. Some systems used in mountaineering have "locks" that have to be moved or "reset" as the mountaineer pulls herself upwards. I suppose this stops the climber from falling too far if they let go of the rope but it explains why you don't see mechanical systems with these brakes right in the middle of all those ropes. Please could you add some comments on the practicalities of each system and why some are preferable in given circumstances?

[@muffledd]

thank you for this video. Always been confused by tensions in pulley systems, this helped a lot :)

[@MichelvanBiezen]

Glad it helped! 🙂

[@52blueberry71]

Thank you for your analysis and explanation on pulleys.

[@Albrecht8000]

Perfect teacher!!! :-) Greetings from germany

[@MichelvanBiezen]

Thank you and welcome to the channel!

[@DNOYPIANGLER]

simple yet best explanation.

[@bfflorida2311]

👍👍👍 this best and simplest explained video on this subject thank you

[@petethewrist]

Take that centra pully system,,, If you were to stick a pin in the top left hand pully so as the pully wheel is stopped from turning,,, Then how much load would be on the ceiling??? I believe it would be the total waight of the load and the pullys and ropes,,?????? Now I get confused as from the way I see it, any force you apply down on the far left rope to lift any effort put on that rope must surely then be the same on the opposite rope and then that force must be transfered through the entire system the ceiling should or surely can only see the weight f the weight and pully system combined at any time, all be it that load is sheared by the three hanging points,,, may be another video to explain ,Lol May be a set up with spring scales onall thre hanging pointsI believe any force down on the left rope will be lots of the two others,,,?????

[@mikewhitehorse2580]

How can the force upon the ceiling be MORE than the actual force of the object?

[@MichelvanBiezen]

The force on the ceiling should equal the weight of the object + force applied to pull it up.

[@achilles1500BC]

excellent explanation sir. appreciated

[@NishantGogna]

Heck yes. Thank you. Best video on the concept.

[@KarlosEPM]

I have a question. In the second case, where all segments of the rope/chord are dealing with 25 N, would the total force (100 N) dictate the strength of the rope required? I'm actually planning on using several small pulleys to bring a bicycle wheel spoke to 100 kg of force, and have wondered if it could be done with a string rated for a maximum 30 kg. Thanks in advance!

[@MichelvanBiezen]

If the maximum extended tension on the string = x, you want enough margin to make it safe and you want a string with strength 2x to 3x

[@Monu_Budaniya]

Best explained....🙏🙏🙏🇮🇳🇮🇳🇮🇳🇮🇳

[@brianroberts5672]

I was confused in the third example. At first I thought the load was suspended from the top left hand pulley. The explanation made it clear the load is attached to the lowest pulley. In an exam this should be made clear, otherwise an incorrect answer of 50 Newton could be made by a student that understands pulleys.

[@sagniksaha7359]

Thank you sir. Clear and concise

[@inlove4rock]

Thanck for this awsome teachings! But i have a question: how does 3rd mechanis, work? i mean isn.t it stucked or something ?

[@MichelvanBiezen]

On the third set, if you pull on the free end of the rope, the bottom pulley will go up.

[@inlove4rock]

@@MichelvanBiezen Thank you!

[@gerhardmalberg4966]

Best explanation found. Thanks

[@plakshman6951]

Best explanation and good fiter

[@aamirmalik1222]

simple nd the best explanation

[@fouzicad7650]

Good explain thanks to this teacher and to channel from algeria

[@MichelvanBiezen]

Thank you! 😃 Welcome to the channel!

[@HarshRajAlwaysfree]

finally I can hear from my both ears.

[@wazumult]

How do I know over which bodies to draw the Free Body Diagram?

[@MichelvanBiezen]

In a way it doesn't matter, since any diagram will work for a particular purpose. But essentially, you want the free body diagram boundary to cut through the line for which you want to find the force or tension.

[@MdIslam-dg1du]

Thank you for your clear explanation sir

[@MichelvanBiezen]

You are welcome

[@shamsheerpeeransab4128]

Very good teaching

[@subhankarchakraborty3361]

Beautiful explanation... Thanks... 🙏🙏🙏🇮🇳🇮🇳🇮🇳🇮🇳🇮🇳

[@lockdownactivities9911]

Hello sir, plz advise , I have 100 N load , attach with 2 different pullies with 2 separate ropes , one is top left other is top right side... i e. this is 2:1, 2 seprate arrangements ...attached with same load... if I pull both the ropes simultaneously...and wants to pul load 1 feet up...will I get 4: 1 advantage...

[@nuavecmoi]

Another great video!

[@MichelvanBiezen]

Thank you.

[@adkhamjonkhamidullayev8008]

The Best Explanation thank you

[@bestamerica]

' some no and some yes... depend on the pulley wheel size

[@luisgourrier7192]

The Romans thermique they use on the coliseum, thanks for sharing.

[@stroys7061]

Outstanding presentation! Thanks

[@canadiannuclearman]

Here is a good question interesting and surprising because of how many people get it wrong. A man sees s single rope go from the floor up over a single pully and down to the floor. He takes one end ties it to his waist. He then pulls on the other rope end and lifts himself off the ground. Q: Is he experiencing a mechanical advantage ?

[@naitikgupta7450]

I think the answer is no. Correct me if i am wrong.

[@malikc3142]

Great presentation

[@lancebaker3132]

At 00:38 "must add up to a hundred pounds". Is that a mistake? Should be 100 Newtons.

[@MichelvanBiezen]

That is correct. (We use pounds here, so it was a slip of the brain)

[@hmata3]

Excellent video!

[@Jon-xq3kn]

Wait, what? In your third example, let's say the supporting structure is a beam that has a breaking strength of exactly 110N. Now let's say that the open end of the system (F=33N) extends to the floor where it is tied to a shackle. In addition to the 100N weight, let's add 1N for each small pulley, 2N for the large pulley, and 1N for the rope, for a total suspended weight of 105N. Are you saying that the beam will break because the pulleys are inducing 133N on the system rather than 105N? I'm not a mechanical engineer, but I don't think so.

[@tan_apek]

isn't no of pulleys = mechanical advantage? for example 1, there are only 3 pulleys but result in mechanical advantage value of 4. any explanation to that? thanks

[@helyadadkhah7059]

thanks it was great video

[@destinydiaz-hall2298]

Amazing. Literally thank youb

[@MichelvanBiezen]

Glad it helped!

[@umitdev7045]

easy but important

[@RajanGupta-po8jb]

I love this video

[@CrookedWoodsFamilyOrchard]

Great explanation, What if I wanna pull out a tree let's say I have 8 pulleys Can I put 4 of the pulleys all on the tree, I'm gunna see if I can pull a TREE out of the ground with a bunch of snach blocks. I mean what could go wrong

[@MichelvanBiezen]

It is very dangerous. The ropes will be under very high tension and if anything breaks or snaps, watch out!

[@CrookedWoodsFamilyOrchard]

@@MichelvanBiezen Got another suggestion for pulling big stump side of the ground other than using a backhoe

[@ColinRichardson]

0:37 100N is not 100 lbs

[@robertalabaster8633]

The pulleys are light pulleys in these examples.

[@MichelvanBiezen]

Yes, these pulleys have no mass and no friction.

[@robertalabaster8633]

@@MichelvanBiezen Excellent video

[@RanjeetSingh-vj3qt]

Sir please tell me what load i would get on winch for lifting load of 1200 kg by using two pulley on top and three pulley on lifting load bar

[@MichelvanBiezen]

That depends on how they are connected. You have to use free body diagrams as shown in the videos to calculate the mechanical advantage

[@RanjeetSingh-vj3qt]

@@MichelvanBiezen thanks sir

[@adityakrsna4853]

In India we generally curious to find acceleration of blocks and yes generally i use imagination . How much string lag and which string pulling that alag 👍👍

[@MichelvanBiezen]

The schools have very high standards in India.

[@adityakrsna4853]

@@MichelvanBiezen yes their is high competition here . These questions are kind of easy for students here . Have u ever see IIT jee advanced paper. Student who are preparing for jee advance use to solve Irodov several times

[@MichelvanBiezen]

Yes, they are very hard tests. We have a number of videos on examples from the JEE MAIN and JEE ADVANCED tests on this channel. (Easily found from the main page).

[@pradipchaterjee9576]

1st diagram from the left Answer or f=25 N

[@ColinRichardson]

I want to live in your world where the pulleys weigh nothing.

[@PV-px5dv]

I want you to do it’s before complete Answer

[@Anonymous-lw4nq]

Good for Jee Advanced 👍

[@MichelvanBiezen]

We plan on making videos on how to take the JEE and JEE advanced tests

[@pranavamali05]

I bet one can crack jee advance just by seeing sir's lecture

[@MichelvanBiezen]

From the feedback we are getting, watching our physics videos go a long way into preparing students for the JEE testing and the NEET testing. (As well as the MCAT testing)

[@logmeindangit]

Hey, wait a minute. In the diagram on the left, he says it takes 125 Newtons of force from above to suspend a weight pulling with 100 Newtons of force? How could that be? Scenario1 : I need to go get a drink of water. I tie a knot in the rope so it sticks in the last pulley. NOW how many Newtons of force are pulling down? New scenario (That would be #2) : I need to eat a cheeseburger. I tie the end of the rope onto the weight. NOW how many Newtons of force are pulling down? I'm going to go have an iced tea - with lemon and honey - and let this sink in a while...

[@michaelrusso3047]

okay, so the weight is pulling down in the y direction as is the free end of the pulley rope on the right. so, in total, the force of the mass and the force by the rope equals 125N downwards, which needs 125N upwards to hold it in place in static equilibrium

[@CertifiedDoc]

The force on the ceiling will always be equal and opposite to the downward force of the system. In lieu of you pulling down, the only weight on the system is 100N. Scenario 1: if you tie a knot in the rope on the last pulley, it essentially eliminates that pulley from the system. It would be the same as typing it directly to the ceiling. Since there's no downward force, the total force on the ceiling is 100N. Scenario 2: This complicates things, but you can still resolve it using free-body diagrams. It's easiest to start with the pulley on the right. If you work through FBDs for each pulley, you'll find that the right pulley is supporting 20N directly, while the left pulley supports 80N directly. The ropes attached to the ceiling have, from left to right, 40N, 20N, and 40N of tension. Therefore, the ceiling again must support 100N of force.

[@carlosalbertocuadros5469]

Good Job

[@MichelvanBiezen]

Thanks!

[@fsilveyra6469]

Great lesson

[@alwanbaghlani]

Very very good

[@MichelvanBiezen]

Thank you. Glad you liked it.

[@alexroyle5766]

I was wondering how the diameter of pulleys affects pulley systems. I would have thought similar to gears

[@MichelvanBiezen]

No, the diameter on pulleys does not matter. It is different with gears since the number of teeth per gear does matter.

[@pikifrino]

Very good +explanatory lesson! Than u

[@joeryerson9295]

I was with this guy until he claimed that ceiling was holding more weight than what was being held up on a a static line. That last pulley is just a redirection of force. You can remove it and attach the rope onto the ceiling and you would still have the same amount of force on the ceiling. If the load is being raised then there would be an increase in the amount of force the ceiling holds that would be proportional to the acceleration of the pull.

[@ianbrown_777]

But it is the redirect that changes the weight. If you tie off, the ceiling is pulling UP with 25N. If you now untie and use the 3rd pulley to apply the 25N by pulling DOWN, you are now adding the extra 25N. Imagine just the redirect on its own with a 25N load balanced with another 25N. There will now be 50N on the ceiling.

[@sadoqataknazarova1427]

thank you very much!!!

[@MichelvanBiezen]

You're welcome!

[@PV-px5dv]

How to solutions

[@deepakdas570]

thank you, sir

[@AdnanAhmed-gg3yy]

really good

[@adam_00707]

Last one is correct?

[@MichelvanBiezen]

Yes, it is. Thanks for checking.

[@sajidjan80]

great... i enjoyed it

[@phb6795]

C'est un problème de 2° (3 années avant le bac)

[@md.salahuddinyousuf755]

Thanks

[@katrinavictimwb]

Do you do any electrical engineering sir?

[@MichelvanBiezen]

katrinavictimwb i will be starting electrical engineering videos this summer There are some videos on electrical circuits in the physics playlists

[@the_chronic_sneezer]

Thank you sir!

[@WalterBeyaz1]

Hocam sorular çok basit. Çarşamba sınavım var. Hadi hayırlısı 🖐🖐

[@rithinv5090]

Good

[@ronnylov]

Thanks 👍

[@adgf1x]

2.F=100/8=12.5N.

[@MichelvanBiezen]

Not sure if you are asking a question of making a statement. (A few words may help out).

[@oraking8379]

thank you

[@wanted1729]

thanks a lot

[@นายอินขอรับ]

ขอบคุณ ขอรับ

[@adgf1x]

F=100/4=25N.

[@MichelvanBiezen]

Not sure if you are asking a question of making a statement. (A few words may help out).

[@karimkhan1312]

sir - execllent -- i think u do research in applied mechanics-- what is u r topic of research

[@MichelvanBiezen]

Amarjeet Singh I also work as an engineer

[@ptyptypty3]

you also work as an Engineer?.,... wow that must be fun!! riding around on a Steam Locomotive Train every day!! (LOL, just kidding Michel!!)

[@logmeindangit]

I worked for a short time with a young man who was educating himself as an electronics engineer, and he just got hired by ... yes, the RAILROAD! Amtrak hired him, and he moved to the east coast, to be an engineer for the railroad - but not driving trains, working in an office somewhere doing engineering work. Cool beans!

[@karthikp2650]

Sir, I did not understand

[@carlosgil9325]

you need to study basic principles of physics.

[@maryammaryam7895]

Revise newton's law on motion in mechanic

[@arifahmad-7261]

🥰🥰🥰

[@aaronthenorm5400]

Are you pullying my leg?

[@MichelvanBiezen]

We sure are! 😄😄

[@electricburning]

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