Why newton's third law is not applicable for non-solid subsatances....?

[Syed Abuthahir]

Hello

 

 

Why newton's third law is not applicable for non-solid subsatances....?

[John Cuthber]

Why have you posted this twice?

[Syed Abuthahir]

i just forget to type the word "NOT" and i dont know how to edit... Sir i am a student and i want to know....

 

Why newton's third law is not applicable for non-solid subsatances....?

[swansont]

i just forget to type the word "NOT" and i dont know how to edit... Sir i am a student and i want to know....

 

Why newton's third law is not applicable for non-solid subsatances....?

 

Why are you under the impression that it does not apply?

[studiot]

All three of Newton's laws always apply in classical mechanics.

 

But you need to apply them correctly.

 

Solids are often considered as a single body for the purpose of mechanics.

But this only works if the applied force is not sufficient to break up the body.

If the force is sufficient to break the body we have to consider the pieces individually as single bodies.

 

With liquids and gases even a small applied force will penetrate and therefore break up the body.

But if we consider the individual fluid particles then Newton's laws work.

 

As to editing, I find that sometimes the edit button that you see at the bottom of your post does not work properly.

 

If you click the edit button then go to Use Full Editor, the edit button works then

Edited January 14, 2015 by studiot

[Syed Abuthahir]

thank you sir

[MomentTheory]

I was just thinking about this today while playing in the bath, (yes I'm 27 and I still like to play with water, it helps me think). I noticed as droplets hit the water and dispersed into waves, there was also water being ejected back out of the point of contact, in the opposite direction of the falling droplet. Assuming that the disbursement of water via waves is the opposite reaction to the introduction of the water droplet, it must be assumed that the body's tendency to be at rest with gravity is what causes the drop to re-eject from the water, the extra force comes from the resistance of surrounding container. Note that under vacuum conditions with no gravity, (like space) this phenomena would not occur. I'm not sure if that is what you are referring to, but that's my 2 cents.

[studiot]

Water has fairly strong surface forces acting in addition to gravity and any atmospheric pressure and container reactions.