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
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
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. 😊😊😊😊😊😊😊😊😊
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....................
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.....
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
I ain't estimating the level of knowledge we have amongst us. But seriously, this is something which we meant to know. A simple intuition anytime in class 10-11 can easily bring this question and gets answered there itself. As a mech gate aspirant, one should be knowing this already but comments made me surprised.
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
Thanks a lot sir !!! I always thought if Normal force is the reaction of mg and Normal force on surface the reaction of the first normal reaction, then it would start a chain. I discussed with many of my peers and couldn't come to a conclusion. Then after much pondering I came to same conclusion as yours, the reaction was mg on earth's center all along. Thank you very much sir for giving me assurance and making me feel grateful to think physics rationally. ❤
I feel very strong in concepts of physic as newtans third law is base for many concepts in physics I stroggled lot due to this.❤ And I am really happy as you made the vedio in English thank you lot.
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
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.
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 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
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 ?
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.
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Sir, or anyone who'll listen, it seems Equilibria occur in pairs as well, as forces do? net Force on my resting body: ∑ F = -mg + N ∑ F = 0. net Force on earth: ∑ F = +mg - N ∑ F = 0.
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
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.
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?
I also have the same question, Imagine you have 1 block and you applied force in it like for an example 15N and we say the block also applied a force on you of 15N then why the block move? since there's a cancellation of force then i assume that it must not move right 🤕
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
7. Which of the following is true about action and reaction forces? A. Action and reaction forces always act on a single body. B. Action and reaction forces are the same type forces. C. A body experiences no net force because of action and reaction forces. D. Action and reaction forces have different lines of action which one is the correct answere
Sir I've a question If force acts in pair then both forces opposite direction should cancel each other so overall there should not be any motion Then how is it possible to have motion Pls pls clear my doubt sir I am really getting very much confusion about this topic Pls reply
See the 2nd statement,They act on different bodies When you walk,you push the ground backwards with your feet. Then the ground pushes you forward (that's static friction) You can see how your force acted on ground while ground's reaction acted on you,therefore there is motion on you.
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).
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
For me, the original statement of Newton Third Laws which was the action force = the reaction force (you change it to "the force occurs in pairs") but in the opposite direction (you change it to "they act on the different bodies") is better and more clear sentence than your sentence. Provide me the appropriate generic force names since you stated that the force happens in pairs. It is not cause and effect concept. It is the concept of load and support.
If a bats man hit a ball which then rolls on a levelled ground. After covering a short distance the ball comes to rest . The ball slows to stop because there is a force on the ball opposing the motion . So my question is which law of NEWTON is applied in this case Sir please explain i am student of class 9th and my exams is very close
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
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.
Light can break Newton's third law: Wimmer, M., Regensburger, A., Bersch, C. et al. Optical diametric drive acceleration through action-reaction symmetry breaking. Nature Phys 9, 780-784 (2013). DOI: 10.1038/NPHYS2777
Sir, you taught that our weight mg makes pair with the force at the centre of earth i.e. Mg' if we let M to be the mass of earth, then how mg can be made equal to Mg' if g' = 0 at the centre of earth then obviously Mg' must be 0 Please make my doubt clear ,Sir 🙏🙏🙏🙏🙏🙏🙏
The Force of gravity requires a mass coupling to be present. Hence there is no force at the center of earth, but there is a sum force IN THE DIRECTION of that center. So if earth was isolated from any other body where would its gravitational force reside? And what is the direction of that force? It resides between the mass of the separate molecules as mutual attraction. This attraction cause the molecules to compact eventually approximating a sphere. So the molecules form spheres layered upon spheres. And since forces in the same direction combine & opposites cancel, we end up with a spherical distribution of forces in the direction of the center of mass. These forces act on the space surrounding the earth & not on earth's center of mass & form a force field in space. Note that what occurs at points inside the earth itself is more complex & was not addressed by Newton. This is what I gathered from reading parts of Newton's Principia Mathematica. You should too, good luck.
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
When we kick the ball ,the ball also exerts some force on to our leg but as the force of our kick is stronger,the ball moves forward..... Then what about Newton's third law of motion. Is it not applicable here..or where did I commit mistake.
You kick the ball, you applied a force, say, 10N on it. Assume the ball is of 1kg, then the ball got accelerated with an acceleration of 10m/s². Simultaneously, that ball applied a force on your foot too with exactly the same magnitude 10N but in the opposite direction. Assuming you to be 70kg and your foot to be 20kg, acceleration of your foot would be 10/20 = 0.5m/s² which is very very small compared to the acceleration of the ball. Therefore, you don't notice the effect of the force on your foot by the ball.
You kick the ball, you applied a force, say, 10N on it. Assume the ball is of 1kg, then the ball got accelerated with an acceleration of 10m/s². Simultaneously, that ball applied a force on your foot too with exactly the same magnitude 10N but in the opposite direction. Assuming you to be 70kg and your foot to be 20kg, acceleration of your foot would be 10/20 = 0.5m/s² which is very very small compared to the acceleration of the ball. Therefore, you don't notice the effect of the force on your foot by the ball.
Good evening sir Sir please help me I am in great confusion 😭😭 Sir please explain that why this phenomenon at 2:51 do not happen 🙏🙏 Plz help me if any one of you can explain it
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.
