Moments, Torques and Levers - A Level Physics

[@lastlaugh98]

If I'm ever confused about a certain topic during a lesson, the first thing I do when I get home is look up one of your videos on the topic and it all becomes clear. Thank you so much, you are a literal life saver.

[@ssskpgt]

Informative yet concise, clear yet detailed, beautiful yet logical. Your videos are pure brilliance and I thank you for continuing your work.

[@tashjacobs6522]

Just wanted to say a massive thank you for making these videos - I personally find them invaluable. They are simple, easy to follow and informative. Thank you again!

[@christellamoza9909]

seven years later, and this dude is out her still saving my exams... thank you kind sir. Your generosity is highly appreciated. I might actually pass physics

[@DrPhysicsA]

Congratulations on passing your A-level. Delighted to hear it.

[@youtubesecure7204]

A lovely video, even 7 years after. Clearly explained every bit. Thank you so much!

[@jinhongouyang8166]

It is still saving my exams now

[@hebar29]

You're the best physics teacher l've ever seen thank you so much for your lessons

[@apopaa3535]

lets do a fund raiser and get him a hd camera

[@alpha.m5483]

No, don't be sympathetic you soft little child.

[@youtubesecure7204]

this video was made in 2013!

[@teddy6354]

Y

[@DrPhysicsA]

Yes you can. I just wanted to show how it is derived from moments.

[@officialgazj]

How long is this piece of paper!?

[@Geo124111]

Banter

[@DrPhysicsA]

Thanks. Good luck in any exams you may be taking.

[@DRandR1productionz]

thank you so much no one has ever been able to get moments through to me properly this has helped me tremendously

[@190miranda]

his voice is so clear!really amazing......i didnt even had to pause,,,,,its so damn perfect!

[@DrPhysicsA]

How very kind of you to say so.

[@190miranda]

DrPhysicsA thank you sir!:-)

[@fisslewine1222]

Really good and clear content, really the world is in need of good lectures like this when maths is involved!

[@rb10bird]

thank you so much! I seem to learn better from watching videos than from teachers and your videos are amazing

[@Cedar843]

Thank you very much for this helpful medium. Such an altruistic gesture that it must surely be driven by passion, and so I know I've came to the right place.

[@ouqassousouhayl7165]

Thank youu so much Dr,i really love your videos,i'm in 4th year in mechanical school engineering in morocco,continue :) greeting from morocco :)

[@hamzabadyi4649]

wow the best teacher i had ever seen until this moment thank you. continue

[@mahmoudm451]

The way our arm is, although not good in terms of mechanical advantage, but it helps us to grow stronger and muscular :D so I love it.

[@omardastgir2985]

24:00 wouldn't you use the sum of both forces?

[@liltune32]

DrPhysicsA - you have helped em tremendously. You have shown me that my way fo thinking in physics was terribly wrong and it has significantly improve since. Thanks a lot for your work sir! ^_^

[@cloudninedreamer96]

Thank you! I've got my physics AS exams next week and this really cleared everything up for me, i was getting so confused as i missed the lesson at college, so thanks again!

[@esabhayat550]

What you doing with yourself now

[@vitoscarletta9267]

You may have just saved my exams...thank you so much dude :) subscribed!

[@swcoast]

With regards to 19:13, I thought the moment of the biceps muscle would take into consideration the distance from where the muscle originates (i.e. shoulder) rather than where it inserts (just past the elbow at the proximal end of the forearm, i.e. 'E' in your diagram). In that case, the distance from shoulder to elbow is larger than that shown in the diagram, and therefore the moment should be larger too. If the distance were at the point where the muscle inserts, i.e. 'E' in the diagram, then that would mean it would be quite irrelevant where a muscle originates, but we were taught in anatomy that a muscle originating further from the elbow joint will have a greater moment than one originating closer to it. Could this just be a case of medics clearly not being physicists and having applied the concept of moments incorrectly? I would really appreciate your help, as this concept is often used as an explanation for the arrangement of muscles, as well as the biomechanics during its actions. Thank you in advance.

[@lahockeyboy]

Thank you again, Professor, for all of your generous and wonderful physics videos

[@DrPhysicsA]

Have you seen my vid on "Classical Mechanics - A Level Physics"? They deal with equations of motion.

[@schmandlaoe5265]

Honestly, you are awesome!

[@DrPhysicsA]

I'm afraid I don't. And I was never much good at chemistry myself apart from physical chemistry which is pretty much atomic physics.

[@nickmccandless7721]

Hey, i am a automotive technician. So if i am Breaking a bolt loose or torquing a large bolt (say a head bolt) with a single arm rachet or spanner wrench. Am i applying a moment to that bolt? we have always said "torque the bolt.

[@Annum212]

Sir your videos are amazing ! The way you explained in such detail helped me understand the topic really well. I request you to start making videos on the recent topics of A levels that has been added to the 2018 specification . I've seen so many videos but I only understand the way you explain. Thank you so much!

[@namnamngomium]

DrPhysicsA; You such a human. Thank you.

[@Playfulzombie]

This was great, could you do a video on the four equations of motion?

[@DrPhysicsA]

I dont know of any reason why you cant. I suppose the key thing is whether you can find an educational establishment that would teach full A level courses in 1 year.

[@mahmoudm451]

at 6:51 you said that we must add all the anti-clockwise forces and then subtract from it "N* distance to the pivot B" why is that? N is the normal force and it's equal to all the anti-clockwise forces, if we multiply it by the distance to the pivot B, the we will get a net clockwise force

[@DrPhysicsA]

+Mahmoud Matar You need to calculate all the clockwise and anticlockwise MOMENTS of the force (i.e. force x distance to pivot point).

[@varunpanchmal8762]

At 7:00. Why do we have to take in account of N?You have changed the pivot point from N to B

[@DrPhysicsA]

Varun Panchmal You have to take account of ALL forces except the ones which go through the pivot point (because the moment of any force thro the pivot point is Fxd where d=0). So when the pivot point is B you have to take account of N.

[@legendfooty]

DrPhysicsA

[@felipemarinho8359]

legendfooty I guess no one taught you respect. The man is a physicist and a teacher, he deserves all respect in the world.

[@jasminfadhilahjapri1611]

DrPhysicsA so does the value of N is in negative value due to its direction?

[@DrPhysicsA]

Jasmin Japri Yes. You can choose any convention as long as you are consistent. One convention is that all forces which would produce clockwise movement are positive - anticlockwise would be negative.

[@anilsharma-ev2my]

Please found out work done by an aneroid barometer in joules per unit volume ? Volume of cell cylinder of an aneroid barometer ??

[@brilliabenny8222]

What is the difference between a level series and GCSE series? Are they same...which series covers the full basics ?

[@johnarnold312]

Why does the mechanical advantage occur? Not how to find it, but why does it occur? I, put 1 pound of downward force in, and if the level is arranged correctly, I get 10 pounds of force out? Where do the additional 9 pounds of force come from?

[@MsZulMoon]

thanks loads.......... :) helped me a lot... passed my a-level well... your videos were really helpful!

[@subramanianchenniappan4059]

Great narration 🙏🙏🙏.I am.trying to revise physics which I studied 30 years back . I am a software developer now

[@youssefsamih]

Thanks very much . We need more videos please to cover the whole syllabus

[@wbcs3605]

Sir, YOUR videos is so nice...sir i request you to make more video regarding NUCLEAR physics and QUANTUM machanics...THANK YOU SIR.

[@DrPhysicsA]

Have you seen the two playlists on these subjects on my channel? kzbin.infoplaylists

[@wbcs3605]

DrPhysicsA thank u sir.....

[@thisnothendismyalt]

@李溟东 i believe the mass is 6.666666 (ext) kg The first step is simply to draw a diagram, it gets easier one you have one

[@willking977]

would you include the weight of the sea saw too when doing these calculations?

[@swajihh]

Sir although we have physics teacher , but you are the best

[@ryanlion7688]

Is this targeted towards a specific exam board or is this general and will require your understanding regardless of exam boards (im asking this because i havent started sixth form quite yet)? Thanks very much for taking the time to post these videos as they are helpful to thousands of people.

[@DrPhysicsA]

My a level series is intended to cover the material in several exam boards including AQA Edexcel OCR and CIE.

[@ryanlion7688]

Brilliant, thanks for responding.

[@quegunsaeracdckisled]

Hello ryan lion

[@zainu0]

Hi thanks for the amazing videos! I needed ur advice on this, I want to do 3 Alevels in one yr, Is that possible? Can u offer ur thoughts on this plss? Thank u so much

[@khaleda.k1124]

do you have any videos of newtons laws of motions in Alevel ?? and the newtons laws of motion in GCSE revision....... is it the same with Alevel physics?? and i need a video on turbulent and laminar flows in Alevels??

[@TheBlazefire33]

love your videos, and do you know someone like you who teaches chemistry on youtube?

[@kimjewelsantos5065]

Mr. Scotty.. beam me up from our final exam later please 😭 live long and prosper DrPhysicsA..

[@auail5594]

Is there a video about lever that also concerns the fact that the lever has volume and that the forces are exerted over an area? I am trying to calculate the torque that will be exerted on a cylindrical shaft by a ring shaped weight.

[@DrPhysicsA]

Au Ail My videos on this subject are for GCSE and A level and I suspect not sufficiently advanced for what you want to do.

[@josephsteers3355]

On the last part isn't 2FD = 2x.0.5x30 = 30 but then Fx2D= 15, can you not use 2FD?

[@funkycude57]

this is my favorite dr physics a video

[@zaza92926]

Do some question as an explanation please .....

[@juegoh4618]

i dont know if this is a stupid thing to ask..but if u want to lift the world as Archimedes said,supposedly u must have a very good MA rite? but how does earth gets its weight? gravitational field? where does the gravitational field comes from? the Sun?

[@DrPhysicsA]

Yes. If you want to lift the Earth then you will need a fulcrum, the earth will need to be very close to the fulcrum on one side, and you will need to bear down on the other side a significant distance away. The mass of an object is an inherent part of it. The weight of an object is simply the mass multiplied by any gravitational force acting on it.

[@inuyasha11p]

Should I do this first or Circular Motion first?

[@DrPhysicsA]

Either really. My A Level revision playlist is in what I regard as a reasonably logical order.

[@Szat1]

Can you please do a video on toppling! Thank you!

[@DrPhysicsA]

Syed ZA Tirmzi See kzbin.info/www/bejne/qIiWdauAg9d6gMU towards the end of the video

[@shawnchin5147]

Hi, i want to know why does a lever works? what actually happens? it seems so magical that the further away the effort from the fulcrum the easier it gets.

[@DrPhysicsA]

Ultimately I suppose that is just the nature of nature. But essentially for things which turn we are looking at a form of force called torque which is the product of the actual force and the distance from the turning point.

[@kimdelarosa7249]

please make a video about Couple Forces :)

[@hritkandel8080]

SO YOU MEAN THAT IF WE TAKE THE PIVOT TO THE RIGHT HAND END , THE BODY WILL STILL NOT MOVE DOWNWARDS ?

[@DrPhysicsA]

+Devious Minion No. I mean that if you are consistent with your signing convention (je whether clockwise/ anticlockwise forces are +ve/-ve) the direction of turning will fall out of the calculation.

[@hritkandel8080]

Thanks , this really helped like all your other videos .

[@mayankmallik3794]

10:41 Except the earth is the source of the gravity itself Seriously though, the videos are awesome

[@TheaDragonSpirit]

A lever isn't affected by gravity in space. You would just exclude this from the equations in space.

[@shakyldanial]

Brilliant Video

[@ChippyTheLengend]

But does load not equal a and does Effort not equal b so would it not be a/b ???

[@DrPhysicsA]

Perhaps you could let me know the point on the video where this arises so I can respond to it.

[@ChippyTheLengend]

DrPhysicsA 13:29

[@mechwurm]

you just need to watch out on these that the Normal Force at the fulcrum is not great enough to snap the lever in half

[@samarthsai9530]

Where would Archimedes stand........... Nicer than nice video, by thanks for the clear explanation ,Sir.

[@purplepowersnatcher]

Thank you for your videos, they're awesome!

[@andrewandrews4059]

*there awsome

[@purplepowersnatcher]

Andrew Andrews They are awesome --> They're awesome. Not there are awesome. :D

[@hassambitw]

+Andrew Andrews: When you try to sound smart but come out a dumbass

[@user-kl8vj2qy9w]

hassam bitw looool

[@V1DE0DR0ME]

18:03... Umm Doctor... that Load... :D

[@LeonePalle]

Wow thanks so much these are too helpful!!

[@jacobvandijk6525]

Can someone give a clear definition of TORQUE? At the end of this video it seems to be "the sum of moments of force". Am I right? I have my doubts.

[@Magiix004]

+Sjaak van Dijk I would define TORQUE as the ability, for a force, to rotate a mass around an axis, or fulcrum. An exemple I love, torque is very important in car engineering, as it is the power of the engine (FORCE) applied on the axis, which does the weels spin. Got it ?

[@jacobvandijk6525]

+Mickele Dellaterra Got it! So what's the difference between torque and the moment of a force?

[@Magiix004]

The MOMENT is the turning effect of a force, like said the Doc. Let's take an example: A flat wood table and a small ball. To move that ball from point A to point B, you are going to push it with a force. The ball will roll in an straight path if you do it the right way. That force is simply called force. Imagine now, that same ball is being attached to a string you are holding in your left hand. In your right hand, you've got the ball. The string is held horizontally. If you let the ball fall holding your left hand totally still, the ball will fall with a force equal to G, that's logic. But since this force is being applied through an axis and the ball is rotating around the point of string you are holding, this force is called MOMENTUM. To be concise, momentum defines a rotating force, which refers to TORQUE. Hope I helped !

[@jacobvandijk6525]

+Mickele Dellaterra Appreciate your answer. Thanks!

[@李溟东]

Hi, doctor, I have a question, could u help me please? A uniform plank of length 1.6 m and mass 4 kg rests on two supports which are 0.3 m from each end of the plank. A mass is attached to one end of the plank. If the normal reaction force on the support nearer to this load is twice the normal reaction force on the other support, determine the mass attached. Please help me!! Thank u very much!!

[@SaintWilliamIII]

I didn't see where anybody had answered, so here is what I got for answers. A=16.49 B=32.98 M=1.05 mass attached

[@SaintWilliamIII]

M=1.05 kg

[@李溟东]

SaintWilliamIII Thank u so much!! I think they are right!! Thanks!!

[@ibadullahabid8207]

well done , sir!

[@anchalyadav212]

where is the torque part of the video

[@DrPhysicsA]

It is covered briefly. But you can also find more information on the dynamics of rotating objects in the classical mechanics playlist.

[@anchalyadav212]

thanx

[@schrod56]

How can 2FD be written as F2d ?

[@masterReca138]

its just a multiplication so it can be done in any order its still the same value

[@alen7648]

Brilliant so far...:)

[@danmcelvenny8378]

fantastic. thank you!

[@VeritasAmantesVocat]

Wonderful!

[@happy......]

just happened to pause the vid at 18:01

[@glamophobic2409]

superb thnx alot

[@АндрейДынин-л8т]

r at least show me what part seems wrong to you. please. May i ask your opinon on another thing. it is about black hole and dark matter. How i see a black hoel and galaxy around it all galaxy objects like asteroind, planets stars have a layer like stracture.Most likely black hole too. As i see it lairs is 1C-2C-3C-4C-5C-6C divided be speed of light (particles found in big colider most like particles from first lair, they stable there, stable at high speed/pressure),the deeper the heavier. (lairs example-lie earth or sun lairs havier to center push lighter up top) Particles constantly fusion and diffusion. example of dark matter from here, fusion and diffusion in 3C cast some particles out of lairs, with higher speed then before (then C3) if it direct down it go to C4 or C5 and fusion and diffusion there, If it direct up it go out of 1C 2C with no interaction with them (do to Einstain already did relativity (no energy exchange or interaction if speed difference is bigger then C)) out ward particle travel to the edge of galaxy (black hole is a biggest attractor and alost non particles can escape for long) the path they travel and they are is a dark matter (mass prlonget in space (compare to us)more then in one place at time) after they lose speed and get attracted to edge most likely the decay, to simple our known speed particles. (they may decay on the way). and they start to move to the BH again,and again, and again. Also, we are in black hole in 0C-1C lair 2C is the blacknes we not see) it looks ok, but sory for bad English, hope you understand me and my view. Basically i see a black hole like this, it is realy hard for me to accept it as single point and big horizone. (i so hubble deep space photos of black hole with sun like surface, it lead me to this) can you please help me calculate it or show me where i can get help with calculation.(put it in formula like stracture) Best regards Dynin A.I. P.S. part of this theory give me rotation namber of black hole and it is 22 years (360).

[@sunke88]

you. are. amazing.

[@aliceontheinternet123]

youre the best!!

[@Chipgargoyle123]

Can you do a video on quantum physics please

[@alpha.m5483]

Are you telling me if nature was more "efficient"I could lift 350 on the incline.

[@michaelgordon6607]

I'm glad I'm taking German, so I know that null is zero. Also wouldn't a centimeter be .01m, and a millimeter be .001. .1m would be a decameter.

[@prijeshkarki9696]

wow it heped me alot ...

[@96MasterOfPuppets96]

Subbed.

[@user-vu4bd6up4k]

ممكن إضافة الترجمة الى العربية كلش محتاجيه 😭😭😢

[@dubtob]

cheers

[@Playfulzombie]

Oh sorry, thank you very much. :)

[@LUNA-zd7jl]

i love physics but i love weed too,can i smoke weed and learn physics?

[@mahmoudm451]

+Marijuana Man Physics needs concentration and even if you do concentrate, it's difficult to hold a full grip on it, smoking weed makes your mind go somewhere else and you won't be able to concentrate and thus you'll fail :)

[@biswajitbhowmik7933]

please upgrade video quality not clear image and therefore not understanding at all

[@user-kl8vj2qy9w]

BISWAJIT BHOWMIK How is it not clear .. u must be joking

[@kahnfatman]

I'm all for the moments but MsG is never good.