Misconceptions in Newton's 3rd Law of Motion
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This video should b viral so that every student has a clear idea of Newton's 3rd law of motion...
Today I have learnt Newton's 3rd law completely
And now I am able to teach it to others with deep explanation
Thanks a lot sir
Who else felt, "My whole life was a lie!" ????
Me
This waste my one week
Nikhil Rajput
I felt it after 5 years of hearing "ache din aane wale hain".....
Half way was wrong 🙄😂
After this lecture I am feeling very proud to my teacher who already told me about this.
Hello sir
Can you explain how Newton's third law is used in case of circular motion
This was the first thing that you spoke about and i was knowing it well beforehand.
Otherwise all of your youtube videos are surprise packages.
😊😊😊😊😊😊😊😊😊
Sir thanks a lot . I have been searching for a correct explanation since I started SHEAR FORCE & BENDING MOMENT
If both the bodies apply a force on one another the reaction will be the opposite forces applied or the normal reaction to the force applied by the body ?
Much appreciated
The thing which many people in comments didn't notice in your explanation normal force
Is due to collision in this case it is contact force keeping body in equilibrium
collision value in this case is equal to mg because it is in rest which is pair of normal force
Force by particle 1 on particle 2 at the same time of instant force by particle 2 on particle 1 are equal in magnitude and opposite in direction along the line joining the particles
Exelent finally i got what i'm searching for we need such teachers to have better understanding of concepts
sir you said that mg is acting on the block itself . but we know that the weight of the block is felt by the ground beneath . then how is the block feeling it's own weight? from what I recall it may experience a stress due to its self weight .
pls correct me if I am wrong
but what will happen to block in case of incline plane
Thanks, this going to helpful in my jee prep and science journey.
Sir if every action has an (equal)and opposite reaction where force acts in pairs and in different bodies how work can be done
May you make a video of force pairs involved in the movement of your arm through air?
I'm thankful that my teachers taught me so nicely. I already had a clear idea about this (I study in India only, in cbse board)
same💀💀
How mg is acting on the box?? The box is giving mg force to the ground and the ground gives a opposite reaction which is also mg. So they act on different object
Yah....here both you mentioned are the action reaction pair
But mg and N are not.
Sir, what will happen if there's no 3rd law of motion?
Pls bring more such videos with the same teacher on other core concepts like Friction too!
Sir why we feel weight because of action or reaction pair
This is simple as in second case there is no contact
Reaction exit if there is action on it
But in second case not such situation
Very nice and short explanation.
The way I always like to see it is to consider that in reality, what happens is that objects INTER-ACT, and a force is really just the partial point of view of that interaction as seen from one of the objects. It follows from this view that, naturally, since down deep what we have is an interaction, then the partial view from one of the objects is directly, and necessarily, equal and opposite from the partial view from the other.
For example, gravity pulls objects together, period. Clearly, though I can see that pull, partially, from object A as "A-mass * g", it is necessarily the case that, from object B, that pulls is "B-mass * g" (and those with opposite direction).
Sir plzz my this doubt that at 6:05 u are saying that mg is acting on box but i seems that mg is acting on surface?????
This problem haunted me for a long time until I saw this video
Really , great explanation 👍🏻
Ye sir to "next level" hai!!
Thank you for making it much more clearer for me!! :0
But when we lift the block upward it try to go in downward.so I am confused 🤔🤔
Just amazing sir
Now i understand newton's third law
Plz tell how 3 rd and 2nd law related
Thanks a lot for explaining. That's a great gap in schools physics program all over the world. And your explanation is very well.
Excellent 1 sir. Thnq 🙂
Sir my question is simple
What if both objects are coming with some magnitude of force then both forces are can be considered as action forces and reaction force of them
Before watching this viedo i thought n and mg are pairs,but for a silly example sir said what if it a block is tied to a string then t=mg,mad i got finally reliased about 3rd law,,i am a 12th class jee student,always a bit confused for these type of hypothetical concepts and even pseudo force etc...anyways thanks for the clarity sir
Thanks for clearing my concept, Also the "N" you're talking of is i guess cohesive force of the material holding at that gravitational potential, i believe it can be classified certainly as electromagnetic of nature
Brilliant, i am feeling light now .
Its my doubt since since 10th and nobody ever even understood my doubt
Trully surprised ✨ Amazeddd 💙💙💙 Thanks a Lot 💙
A great short book to understand this concept and others is "A Student's Guide to Newton's Laws" by Sanjoy Mahajan.
Thank you sir , your explanation is too helpful for me
Why do we say it as Normal reaction force sir?
Sir, but according to third law of motion there should be two different bodies but here you had taken three bodies as the person who is pushing a block , Block A &Block B so here third law of motion will apply between person and on the Block which he/she is pushing
eg. A person swimming in water
So here the two different bodies are person who is swimming and water in which he is swimming so here third law of motion will apply as person will apply action on water to move it back and water will apply reaction and move the person forward
Am I clear in my concept or not please reply sir
Sir pls reply back
Someone plz tell me that how is it possible to move objects if every action has an equal and opposite reaction like if I move a table,the table exerts a force on air particles and the particles would also apply force on it....if we even increase the force the reaction would be more
This is video is such a lifesaver. I was stuck to a problem and took a lot time. But this video cleared it🤓
Nice explanation but wanted to add one more thing that nature of forces of action reaction pair is same as mg force applied on block is gravitational force then it can have a reaction of mg(gravitation force only). Similarly N is the contact force so it's reaction pair will be a N only
Thanks 😊 you sir for providing me with the right content!!!!!🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏
mg is given by the block on the surface and N is given by the surface on the block so I think mg and N are action reaction pair in this case....................
One doubt sir! when you try to move a block by some force the block moves but according to Newton's third law the block shouldn't move as there a equal and opposite reaction they cancel out.
Note: the force are already in pairs as 1) the force applied by you 2) the friction by your foot and ground 3) the force by the block in opposite direction 4)the friction between the block and ground
It's too great u have explained it very well
The normal force arises due to pauli's exclusion principle(in principle)....At microscopic level the electrons on the block tries to push the electrons on the table but it is repelled by the electrons of the table. Now matter as a whole is neutral. The electrons has distribution inside atom right. Then we try to distort the electron distribution of the atoms of the table by the electron distribution around atom of the block. But pauli's exclusion principle doesnot allow to do that. That is kind of the story with the normal force.....
Yeah, exactly. Other non fundamental forces like tension, spring, friction too arise similarly from Electromagnetic force.
sir, in 2:20 if A and B are attached, aren't they the same object . so, there should be no force acted by A on B
Sir but what about your question at 3:00.I am confused about that.Plaease answer about that
Best explanation of third law I have seen so far. Very good!
Difference between contact & adhesive force???
THANK YOU!! Great explanation and correct!!
❤❤ty , this is just what i truly needed and wanted to see
really amazing concept.....
Sir I cannot say anything...I was shocked by the concept. Thank you so much.
how mg is acting on block itself ,
But N is acting on the same body.. Does it violate the second statement??
@exergic sir plz make a video on how to analyze FLTs
Sir i have a question"if we throw an iron ball on surface it does not follow Newton 3rd why?
Mg=N in this case so it cancel out
How he explains such topics easily?
Sir, what will be the net force of action and reaction forces? Is it balanced or unbalanced?
It is balanced with no net force
This statement is meaningless. We calculate net force acting on the "same" body. Not different bodies.
Just wow !!! 👌
wait wtf just happened at 9:56 , Yes upward forces(I:e mg +n) is equal to normal forces (also mg + n) , but how could you cancel out mg from (one side ) & n from (the other side) ....Arent they both collectively equal? for eg. lets take mg=5N and n=10N ....which would be (5+10)=(5+10) now , as like what u did, (10=5) .can anyone explain what is wrong in my intepretation/understanding.
Okay how the box is stable? When the net force is zero then something can be stable no movement. But what causes the box being stable I mean we can't cut action and reaction force because they work on different object.
So does gravity have a force pair then? What bodies would that act on?
Would it be acceleration?
In the (N=mg) as both the forces are equal and opposite the total net force will be (0) and the 1st law says (if no net force acts on body) so you get the point that (N=mg) is also accurate
Just a changed oerspective
Sir, i am in 11th grade althought i have flummox in 3rd law thanks for such a good explanation.😍😘😘😘😘😘
Sir, please ye bataie ki unbalanced condition me uniform acceleration kyu hoti hai. Uniform velocity kyu nahi hoti ??
Unbalanced condition me acceleration aati h. Ye law h. Isse question ni kr skte. Isse experimentally check kr skte h. Agar results sahi aa rhe h, to ye law correct h, ni aa rhe h to galat h. Aur isse indeed results sahi aate h. Physics ke laws are like guesses to the actual laws of the working of the nature. Sahi hua, to sahi. Galat hua, to naya law guess kro.
Still, isse related topic h noether's theorem. It says why conserved quantities like energy, linear momentum or angular momentum are conserved.
Thank you so much sir u explain outstanding ❤😊
Sir can we expect any updates(content wise) in engineering mechanics study material
Yes. For GATE 2021, full study material is going to get updated, including mechanics.
Here, the block exerts a force due to its weight on the inclined plane . But where is the reaction force for that provided by the inclined plane. You have only told about the force of attraction with the earth?
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Sir if mg is also applied by body on centre of earth in reaction of mg applied by earth on body. So both the forces should have cancel each other then when every body is attracted towards centre of earth
Sir if the there is equal and opposite reaction then why do we weight ?
Really thank you for your demonstration..... and i really understand your explanation 🙏🙏🤍
Sir mg will not act on ground
What is the pair of normal reaction in 8:59
Can u please explain the example of horse and cart
In 6:07 mg is acting to the surface and not to itself.
Please clarify
Also forces of action and reaction can not cancel out each other....But u have cancelled?
Ur right but two objects can't be taken as pair,if call A and B wil also come that is pair so tabe and objects are not pair
Why and how u cancelled mg to N ?? . And how all of the forces were equal ?
@SAFWAAN UDDIN no !
I wanna asking u about fuse in space how we apply 3th law of newton there!!! There's vacuum space
9:52 sir that N will react on the surface because forces pair will act on dif bodies
Very valuable video.Thank you
Thank you!
Thank you so much it cleared my doubt
There is opposite force not an equal force.That's the meaning.Imagine the air blower of bernoulli if you apply force in the ball going up it cannot continues to going up cause downward force cause by gravity pushing too. Thats it
Tension force ka bhi opposite reaction hoga ki nai
Excellent explanation sir! Subscribed!
Ok, understood but there can be one more point of view, if a force mg ( by virtue of some object and gravitational pull of earth towards its centre) acts then as you say, force occuring in pairs, so there is another force because of first one ( the tendency of this force is to pull the earth towards object). The action point of this force is earth centre, and since force is a vector and we can move the vector in space ( because force is a true vector) then we can assume normal force is a vector which moves from earth's center to the surface and acts on object.
And also this all aceepts by Newton's first law. There is no motion.
Sir your explanation expression and speaking type are similar to my english teacher
6:18 It is also NOT happening because of the 1 law, but rather 2nd law.
2nd law is, ΣF = ma , if you put a=0, then also ΣF = 0. Then, the 1st law is derived from the 2nd law. There is no need for the 1st law, right? No. Laws in physics are not light things. Laws are not corollary of other laws. Something is not given the status of a law unless it has something very important and different to say. Then what is 1st law actually saying?
Just like the 3rd law, Newton's 1st and 2nd laws have very much confusion to it too. If you are interested, you can read further to get everything clear, I am going to explain everything from scratch.
Story starts from force.
What is force? (pause and think the answer)
Force is an interaction between two objects due to some of their properties.
The knowing of one body that the other body exist is force.
Then, we will see further, the body reacts to that knowledge that other body exists by changing its velocity, i.e. by accelerating.
Now, there are only and only 4 Forces in nature (4 fundamental forces), two of which are significant only inside the nucleus (strong and weak nuclear forces) and the other two being significant in the bigger world, i.e. Electromagnetic force and gravitational force. Naturally, we would discuss only these two bigger forces.
EM force is given by Lorentz force law, F = q(E + V×B)...(charge-charge interaction)
Gravitational force is given by , F = (GMm)/r²...(mass-mass interaction)
From these, we can infer that forces are not dependent on the reference frames.
How? Force depends on charge, mass and length. All of these are frame independent (in non-relativistic mechanics). Therefore, Force is also frame independent.
But by our knowledge of Newton's 2nd Law, ΣF = ma, we get to know that forces are dependent on reference frames. (Since acceleration is frame dependent and this law relates force with acceleration).
Therefore, there is a certain problem here.
Which one is correct? Which correctly defines forces? Fundamental forces laws or newton's second law? The answer is clearly fundamental forces laws, since they are the definition of force.
So is the Newton's 2nd law wrong? In most cases, yes. But there is a special case where it not wrong. There is a special frame of reference where this law holds correct. That frame is named inertial frame. Therefore, NSL is a conditional law.
• 1st and 2nd Law
1st law defines that special frame, the inertial frame. 1st law gives the condition for the validity of the 2nd law.
"If in a frame, ΣF = 0 (by fundamental force laws) on an obj implies a=0 of that obj, then in that frame , acceleration of any object is equal to ΣF on that obj divided by its mass, i.e. a = ΣF/m"
1st law does not say that if ΣF = 0 then a = 0. It says that in any frame where this is true, you are free to apply 2nd law from that frame.
This is precisely what 1st and 2nd laws says.
But, how are going to find that special, inertial frame of reference?
By the law, we first need to find an object on which ΣF = 0 (by fundamental force laws), then find a frame such that the acceleration of that obj wrt that frame is also zero. Then, only a force can cause an acceleration in that frame. Bingo! We have found the inertial frame.
But wait? Is this practically possible? Is it practically possible to find an obj on which ΣF = 0 ? No, it isn't. Every object is applied by an uncountable amount of forces from different celestial bodies. Not only the Earth is applying the gravitational force on us, but also the sun which keeps us revolving around it, and also other parts of the galaxy, which keeps us revolving around the blackhole at the centre of our galaxy.
Therefore, it is impossible to find an obj with zero net force.
What we do then is a very clever approximation, which I'm not going to explain here.
The results get us the practical definitions of inertial frame, which are,
1. If you are close to the earth(or any other planet) and the rotation of the earth is not talked about, then the surface of the earth is taken as the inertial frame (along with all non-accelerating frames wrt the it).
2. If you are close to the earth and rotation is also considered, then the axis of the earth is taken to be the inertial frame.
Great
But correct me if I am wrong
I state it as FOR AN ISOLATED SYSTEM ACTION APPLIED FROM ONE BODY TO OTHER IS EQUAL AND OPPOSITE TO REACTION BY OTHER BODY TO THE FIRST BODY.
Awesome 😊👍 and great 👍👍 video
After searching on Google I am here to understand this topic.Thanks ..