If it doesn't agree with experiment, it's wrong. Part II

[pgimeno]

Why do you keep bringing up scale?

Because magnitudes depend on scale, and as it has been established, magnitudes matter.

 

[pgimeno]

You are entitled to your opinion. When you consider that you are still discussing scale when it has been prove to be irrelevant is proof that you might be the one fantasizing about something.

It has been proved that it's relevant, and that you believed that it's irrelevant because of your misunderstanding of basic physics.

 

[Mark F]

It has been proved that it's relevant, and that you believed that it's irrelevant because of your misunderstanding of basic physics.

I am curious, if scale does not matter, does that mean if Cole's experiment was repeated, but scaled to more accurately depict the actual event, would the result be the same?

FF, got a thought on that?

 

[Criteria]

"Because you don't understand that gravitational forces are equal and opposite, you make the mistake of thinking that the normal force is the reaction force to the gravitational force on the building, which it isn't."

Since gravity is a function of mass, how can the gravitational force exerted by two objects of dramatically different mass be, "equal and opposite"?

 

[NoahFence]

OK. This goes back to something I said at the very beginning, or near the beginning of this thread. You can claim the collapse was started by whatever you want. The issue is not that the collapse occurred. The issue is what was observed during the collapse.

Let's take this further.

This entire thread is about Cole's experiment. Cole does not make any attempt to show what started the collapse, and neither have I. Cole's experiments are only to try to replicate the motion observed during the collapse, and nothing else.

And you have made no attempts to contradict reality. What is your alternative?

 

[DaveThomasNMSR]

You are wrong. The force that the earth exerts upon the building, which is equal and opposite to the gravitational force the building exerts upon the earth, is called...

gravitational force.

You refuse to listen to me. Fine. The two sources I have linked say you are wrong. Actually, any credible source says you are wrong.

http://www.sparknotes.com/physics/dynamics/newtonapplications/section1.rhtml



https://www.khanacademy.org/science...ontact-force/v/normal-force-and-contact-force

If you want to continue to claim that you are right, please copy and paste the relevant text or point out where in the video your statement is confirmed.

I realize that no one will admit that I'm right. So, if you want to continue to play your game, from now on you are going to have to claim credible sources are not right.

NO, it is you who is obviously wrong.

Let's make this easier for you. Imagine that the building is not resting upon the earth,but rather, orbiting the earth, just like the International Space Station.

There are no "contact" forces involved at all. There is no "normal" force, period. There is no drag upon the orbiting tower. There are only gravitational forces.

Now, can you finally see that the gravitational force the earth exerts upon the building is equal and opposite to the gravitational force the building exerts upon the earth?

 

[DaveThomasNMSR]

Since gravity is a function of mass, how can the gravitational force exerted by two objects of dramatically different mass be, "equal and opposite"?

Easy. For two bodies M₁ and M₂, separated by a distance R, the force exerted by M₁ on M₂ is GM₁M₂/R², where G is a Universal Gravitational constant.

Get this: the force exerted by M₂ on M₁ is ALSO GM₁M₂/R², where G is a Universal Gravitational constant.

They comprise what is called an "action/reaction equal and opposite pair of forces."

You're welcome.

 

[Belz...]

There is a difference between relevant and cherry-picking. If you obviously don't understand the first part of Newton's post, what on earth would make anyone think you could understand the rest?

So now we have a second part to a thread simply because you are utterly unwilling or incapable of admitting to being wrong.

 

[pgimeno]

Since gravity is a function of mass, how can the gravitational force exerted by two objects of dramatically different mass be, "equal and opposite"?

See Dave's post 173. I started to write something along these lines, but later I saw that it was answered and didn't post it.

The forces are indeed equal. The accelerations they induce are different (a = F/m). The Earth laughs at a 500N force, because with a mass of approx. 5.972 × 10²⁴ kg, the acceleration it exerts is about 0.00000000000000000000008 m/s².

 

[Belz...]

You post this and expect people to take you seriously?

Ok, let me help you out: the post you were responding to is known to experts as a "joke".

 

[Dave Rogers]

Since gravity is a function of mass, how can the gravitational force exerted by two objects of dramatically different mass be, "equal and opposite"?

Further to DaveThomasNMSR's complete, concise and correct answer, I suggest you too read the Wikipedia page on Newton's Law of Universal Gravitation^WP and start learning some of the fundamental basics of the subject on which you so love to lecture others.

Dave

 

[DaveThomasNMSR]

What causes deceleration? Deceleration is caused by acceleration in the opposite direction. Do you want to disagree with that? Start there. Prove that statement is wrong before I continue.

Once again you are taking your arguments to absurd levels to prove I have no idea what I am talking about.

I know how you are defining deceleration, and your definition is not wrong. You are simply taking my words, and then doing whatever you possibly can to try to prove I misunderstand a concept. Your tactics are beyond absurd.

Deceleration always means a reduction in velocity. Always.

If a large massive object is accelerating (say downward due to gravity), and collides with another object, that collision might alter the total acceleration, perhaps even reducing it (making the magnitude of the acceleration smaller).

But, there will be no deceleration, unless the total acceleration is reduced to the point where it changes sign (and thus, has to go through a "zero").

If there is deceleration, the massive object will slow down. If the deceleration is sufficient, the object might even slow down to a stop, and eventually reverse its direction of motion.

You fail to grasp this bit of elementary physics.

 

[Belz...]

My conclusion is ridiculous? Wow. If an object is accelerating downwards and it impacts another object, Newton's third law tells us what will happen. The accelerating object will exert a force on the object it strikes. The object it strikes will exert an equal and opposite force on the accelerating object. If the accelerating object encounters a force in the opposite direction, what must happen? It will decelerate at the instant of impact. Are you really going to try to tell me that I am wrong, or that this is not true?

You're wrong.

First of all, in a lot of cases the opposing forces will definitely NOT be equal. For instance, if you punch a piece of paper, it will most definitely NOT exert an equal opposite force, and will break, tear or buckle.

Second, there is a difference between "it will decelerate slightly" and "it will stop entirely".

 

[WilliamSeger]

I actually need to change this statement from post 135.

The following statement is true. An accelerating brick will exert a force on a piece of rice paper at the instant of impact. The piece of rice paper will exert an equal and opposite force on the brick. This equal and opposite force will cause the acceleration of the brick to change at the instant of impact. The magnitude of this force will be minute. A minute, instantaneous change in the velocity of the brick will have a minute, instantaneous change on the acceleration of the brick.

Congratulations. Let's extend the thought experiments: I predict that if I gently place a brick on a piece of tissue paper and it can't hold the brick's weight, then if I drop the brick on the tissue paper, it will not cause the brick to decelerate; it will only cause a brief decrease in the acceleration due to gravity. Now, if I place the brick on rice paper that can hold that weight, then I predict that it can cause the brick to decelerate when it's dropped. Can it decelerate the brick all the way to zero and stop it? I predict that it will depend on how far it drops. I claim that I can explain all three of these results with Newtonian physics.

Do you agree with those predictions? Whether you agree or disagree, please use your understanding of Newton physics to explain your reason.

 

[MikeG]

......But, there will be no deceleration, unless the total acceleration is reduced to the point where it changes sign (and thus, has to go through a "zero").....

I'm not sure whether poor old FF hasn't grasped the semantics of the difference between "reduced rate of acceleration" and "deceleration" or whether he hasn't grasped the actual difference. Whichever, as it has been explained a hundred times, would be a major embarrassment to anyone else.

 

[pgimeno]

Further to DaveThomasNMSR's complete, concise and correct answer, I suggest you too read the Wikipedia page on Newton's Law of Universal Gravitation^WP and start learning some of the fundamental basics of the subject on which you so love to lecture others.

To be fair I don't recall Criteria lecturing others on physics; that's FalseFlag's speciality. I see Criteria asking to improve his understanding.

 

[Belz...]

This statement proves that you do not understand Newton's laws of motion. I can't do anything else to help you. I have clearly shown that different forces can have the same magnitude and be in opposite directions.

Myriad has already explained where your mistake is: the two forces are not a reaction pair. Newton's law does NOT apply to them. They thus do not need to be equal, even if they "can", whatever the hell that means.

You refuse to listen to me.

That's because you are both wrong and wilfully ignorant, on top of being condescending and adversarial.

You just proved Cole right. You CAN replicate the motion of a car wheel with a windmill sail.

But don't you see that the two aren't the same? Or is turning sufficient?

Please copy and paste the text where I allegedly say this.

This seems to be your M.O., here. Perpetually pretend to never have read any argument or statement, and constantly ask other posters to do the same work over and over while you continue to ignore it.

 

[Dave Rogers]

To be fair I don't recall Criteria lecturing others on physics; that's FalseFlag's speciality.

True, but inability to understand the physics of 9/11 is a major component of most of the... I was going to say conspiracy theories, but vague suggestions would be a better description. Understand the physics and you start to see through the truther smokescreen, and it gets a lot harder to take the podium and rant about how everyone who believes al-Qaeda carried out the attacks is a liar or a fool.

I see Criteria asking to improve his understanding.

Until he realizes that reality contradicts his beliefs, at which point the abuse recommences.

Dave

 

[PhantomWolf]

He was trying to replicate the motions observed during the collapses of the twin towers. I can't believe I actually had to repeat that.

So then it clearly has nothing to do with any conspiracies of Truther claims, so why is this thread in this forum?

 

[WilliamSeger]

How would a misunderstanding of action-reaction pairs affect my ability to understand what happened during the collapse of the three buildings?

I explained that before and you just farted in my general direction. In the collisions, the action-reaction pair of contact forces are caused by (but are not the same thing as) the combined forces of gravity and inertia. The actual force that's applied to the structure below, however, is limited by how much force the structure can sustain. If it can absorb the combined forces of gravity and inertia without failing, then the collapse halts; otherwise it continues. Now here's where the difference between "caused by" and "same thing as" matters: The actual force that gets applied to the structure below cannot exceed the force that it takes to collapse the structure, because that's the maximum reaction force that the structure can provide. Whatever that reaction force is at the time the structure fails, that's all the force that acts to slow the falling mass, regardless of how much force is available from gravity and inertia.