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Is Newton's third law of motion wrong? Could the other ones be?


Windevoid

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I hope the documentary, school, and college versions weren't different than the original.

Unless, of course, the original was checked and parts were obviously wrong.

No, It rather suggests that you don't understand what you are talking about.

It's a bit like saying

"I heard on the radio this morning that there are 1.5 dollars to the pound.

Does that mean I can sell 150 Zimbabwe dollars for £100?"

The answer is no: you are talking about different things. The US dollar exchange rate doesn't apply to the Zim dollar.

 

Now, as you have been asked before:

"Can you just write newtons third law as you understand it in your next post, please so we are all on the same page. "

"Can you just write newtons third law as you understand it in your next post, please so we are all on the same page. "

 

I just said what I think if means a couple of posts, and a few hours, ago.

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The energy is secondary and is supposed to follow along with the momentum conservation and balance of forces explanation that Swansont gave, right?

"Also, you will not get momentum conservation if you have external forces applying."

 

Does that mean I'm right?

 

No. Five different people told you you were wrong. How is it possible you can ask this?

Every energy/momentum/force is supposed to create an equal and opposite energy/momentum/force when a collision occurs.

 

This is wrong. The third law only mentions force. The momentum conservation can be derived from it, but energy can't. Energy's a scalar anyway, you can;t have "opposite energy"

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I have studied them.

Unless, of course, the original was checked and parts were obviously wrong.

 

You don't get correct answers with your current "everybody but me is wrong" methodology. It doesn't work well for you, unless you're just trying to avoid hard work, or are trolling science forums by questioning basic theories high school students understand. You show in virtually every post where you criticize something that you simply don't understand it, and worse, you have only your own incredulity to support you.

 

If you really have studied these laws, you reached an impasse where your questions obviously stopped you from going farther. That's when you made the mistake in thinking that everyone else in the scientific community is wrong and you're the one person who is right. I know it's easier to try to tear something down than to build on it, but at a certain point don't you have to ask yourself why you're handicapping your own knowledge like this, giving up on the free opportunity for learning people are offering you here at SFN?

 

Sorry, I've probably gotten too personal, but I'm still not sure whether you're just a troll having a laugh getting people to explain basic science and making them frustrated, or someone who has fallen into some bad habits and needs some help.

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I think I am right, though.


Momentum always comes from somewhere and goes somewhere. It never simply appears or disappears. However, if you are studying the collision of two objects and don't control everything else, there are places that momentum can enter or leave the collision other than the two objects in question.

If you take whatever else is having an effect on the system into account, momentum will be conserved.

Where does the friction factor into that?

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I think I am right, though.

 

That would be a problem. You don't cite any theoretical or experimental reasons why it's wrong, and by your question of what experiments have done to support it, you tacitly admit that you haven't investigated the matter yourself. That's not a very good trifecta. All we have left, it seems, is that if you don't understand something, then you think it's wrong. That's not a very good trifecta.

 

Furthermore, it is contrary to rule #1 of speculations. What's more, you have run into this issue before and been warned about it.

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I think I am right, though.

Where does the friction factor into that?

Nobody else ever will unless you can explain why you think that and also explain away hundreds of years of experimental evidence (and, let's face it, you won't - not least because you can't be bothered to do the basic study)

Bringing in friction illustrates my point about the Zimbabwe dollar: It's important in its place, but not relevant here.

You really need to learn more before you seek to criticise.

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Where does the friction factor into that?

 

Friction is an external force, in most cases where the objects rub the ground. In the case where it is an internal force:

if two objects rub against each other, by Newtons third law, the friction forces will be equal in magnitude but in different directions for each object respectively.

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Friction is an external force, in most cases where the objects rub the ground. In the case where it is an internal force:

if two objects rub against each other, by Newtons third law, the friction forces will be equal in magnitude but in different directions for each object respectively.

 

 

Friction always obeys N3.

What is often overlooked is that the action and reaction always act on different bodies, whether due to friction or otherwise.

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I think I am right, though.

 

Where does the friction factor into that?

If an object has a frictional force applied to it by the ground, the object will apply an equal and opposite frictional force to the ground. If the object is slowed to a stop by friction, its momentum will have been transferred to the ground.
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