Are Newton´s assumptions really true?

[Now.You.See.Me 202]

Are Newton´s assumptions really true?

 

here are the laws:

 

First law: When viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force.

 

Second law: F = ma. The vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration vector a of the object.

 

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body

 

I think there is something very wrong with them

 

Let´s start with the last one.

 

When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body

 

Is this really true? Is there good proof, or is it all just nonsense?

 

people really think a floor is pushing back????

 

I have to laugh

[Cyborg 3,189]

Okay this is off-topic discussion section, but isn't it a bit too off-topic and lame?  :huh: Newtons theories do work in general, can make it out from practical experiments.

Edited November 15, 2016 by Cyborg

[Ambitious 2,084]

Go out on the streets and punch someone

thats enough to prove if newton's 3rd law is true or not

[r_I_already_won0 2,339]

Lol...I love how you attempt to disprove a many-times-over proven theory that has stood the test of time for 400 years or so...Can't really tell if you're serious or trolling but 

 

yeah, Newton's laws are Correct. :D Your mind may not be, though ;)

Edited November 15, 2016 by r_I_already_won0

[BlackWasp777 4,498]

 

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body

 

Is this really true? Is there good proof, or is it all just nonsense?

 

people really think a floor is pushing back????

Yes, it really pushes back. Or.. in other words: you push yourself back

 

A usefull example that teaches physics and interpersonal relationship, for force and tension, is a married couple floating in space.

 

 

By an accident their security rope back to the shuttle has snatched.. the do have a firm grip on each other, but both float constantly 20 meters away from the shuttle, slowly rotating too. They have no thrusters in their suits.. so they are in deep trouble.

Illustration:

  woman :wacko:- :mellow: man.................... [space ship]

 

 

 

So while the woman says "oh we are lost, but at least we die together.. I love you..", the man thinks about Newtons Law, his countries law (jurisdiction), and the basic laws of female psychology

            :wub: - :ph34r:  .......................  [space ship]

 

 

He looks at her.. then he looks down.. "sighs..". He waits until his back points toward the shuttle and then he says "you know.. I love you too, but I ****ed the female pilot instructor in the simulator a week ago".

            :blink: - :( ........................  [space ship]

 

 

His wife gets so angry, that in a reflex she gives him a hard push.

            :angry:<-> :rolleyes: ...................... [space ship]

 

The push of the woman make them BOTH move away from their combined center of gravity!

The forces applied on mass translate into accleration and result in speed; so now they just float

The woman floats faster into outer space (less mass).. while the man floats (little slower, more mass) back to the shuttle.

           :angry:   -   :rolleyes:  ....................  [space ship]

        :blink:      -      ^_^ ..................  [space ship]

     :o         -         B) ...............  [space ship]

 

Short checkup:

Newtons third law: unbreached (she pushed him -> so an equal force was applied on both of them)

Coutries law about murder: unbreached (she pushed him liberately & so pushed herself)

Laws on a wife's psychology: unbreached (I better do not comment that :))

 

Then he moves in the shuttle, gets into the pilot seat and picks her up in outer space. In the meanwhile he explains her through the com link, that he was just kidding on her in order to save their both lives.

<_<         sp B) ce ship <..<...<.....

 

Happy end.

--

 

 

Now get on your drawing board and draw those two in outerr space. Draw her force as a vector.. and you will see that this vector will only make him move. Hmm... Fail. You need a second force that pushes her too. But he never pushed her.

In fact it was _her_ force that was divided up between both of them (50%-50%) and causes acceleration (in reversed relation to their mass) that made him move _and_ her move.

You have two force vectors that sum up to zero (center of gravity of both is not influeced by the push).

 

 

 

So a body that applies a force to another body, gets parts of his own force back.

In order to paint it, they do it according to newtons third law, which makes sense from this point of view.

 

It also works with pulling. If the man was still attached to the shuttle via the security line, he could pull himself back. But this would also cause the shuttle to move towards him. The force is again split up 50%-50%, and the movement accelerations are in reverse proportion to their mass (he will accelerate fast, while the xx tons shuttle will acclererate.. well .. not so fast).

Edited November 15, 2016 by BlackWasp777

[newrohan 1,040]

There is for every force an opposite force that acts. Though it may not be visible on one or both the bodies because of their inertia(or other factors). When we push the floor vertically downwards(or even if you dont, you weight puts a force on the floor) the floor pushes you with the same force. It is this force due to which you are able to stand on the floor and dont sink down or rise up.( you would rise up if the force by floor was more)

If the force is not completely normal as happens when we walk, we push the floor backwards while the friction of the floor pushes us forward making it possible for us to walk.

Similarily the law holds for any situation you imagine, though we might not always be able to see it.

Edited November 15, 2016 by newrohan

[beaku 2,656]

Let's not go to Newton's laws yet. Let's come down. To the base. Have a little faith, will you? All of science works because we have faith in the basic axioms.

Take Euclidean geometry, for example. One of the postulates (5th) says that 'if sum of interior angles of two lines with a third line is less than 180°, then those two lines produced will meet each other.'

Now, while this seems obvious, it fails completely when you curve the spacetime in which the lines are made. Curved spacetime was proposed by Einstein's General Relativity. Hence, in space, you won't be able to apply this postulate.

Another example, gravitational force. Out of the four forces known to us in the universe, gravitational force is the weakest force. Now, how do we know it's a thing? How do we know Gravity isn't just an effect of a more subtle phenomena? Or maybe even a much larger one? We have to have some beliefs upon which to work. When we use gravitational forces in our calculations, we assume that all parties having the property known as mass will also be affected by Gravitational forces.

Newton's laws are perfectly applicable in Clasical Physics and that won't change until our understanding of physics does.

[Now.You.See.Me 202]

Nerds  :mellow: 

[Duchess 741]

Nerds  :mellow: 

Nerds are cool. Enough said.

[r_AdvocatusDiaboli0 861]

 

When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body

 

Is this really true? Is there good proof, or is it all just nonsense?

 

people really think a floor is pushing back????

 

I have to laugh

 

Almost-MechanicalEngineer here, Punch a wall

Edited November 15, 2016 by r_AdvocatusDiaboli0

[L.I.I3.3.I2.T.Y 820]

Believe me, you cannot proof that black is white.

[r_I_already_won0 2,339]

Believe me, you cannot proof that black is white.

You mean you cannot prove that black isn't white? :D

 

Read the Philosophiæ Naturalis Principia Mathematica and you will see that these laws are proven...

[L.I.I3.3.I2.T.Y 820]

 

 

Read the Philosophiæ Naturalis Principia Mathematica and you will see that these laws are proven...

That's what i just said

[Ninja 10,468]

Something falls, it hits my toe, I blame Newton. Poor guy. :(

[jazz20 1,181]

Science is man's explanation of the perceivable

[monkeyburn 13,567]

How are you ever going to learn anything if you don't do your own homework?