Newton's Third Law
Ron Hitler Barrassi wrote:
>
>
> Kevin Gowen wrote:
>
>> Ron Hitler Barrassi wrote:
>>
>>>
>>>
>>> necoandjeff wrote:
>>>
>>>> Ron Hitler Barrassi wrote:
>>>>
>>>>> necoandjeff wrote:
>>>>>
>>>>>> Ron Hitler Barrassi wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>> Nice try but I didn't say "200kg of mass".
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Yes, but it would have been better if you did.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> No. It's 200kg of force not mass. This force comes from
>>>>>>> accleration. Newton's First? F=ma.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hey Brett. Even Kevin's little poodle understands that you have
>>>>>> consistently been talking about mass as if it were a force. Mass is
>>>>>> measured in kilograms buddy., acceleration is measured in meters per
>>>>>> second squared, and force is measured in Newtons (not,
>>>>>> unfortunately, Einsteins, though we may understand if you were
>>>>>> confused by this.) A Newton is, surprisingly enough, equal to the
>>>>>> force required to accelerate 1 kilogram, one meter per second
>>>>>> squared, as suggested by F=ma. It's good of you to throw out that
>>>>>> equation 3 or 4 times in the same thread, but you might want to take
>>>>>> the time to understand it first. Arf, arf!!
>>>>>>
>>>>>
>>>>> g=1
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> That was a beautiful butsurigaku non-sequitor, Brett.
>>>
>>>
>>>
>>>
>>> It's not a non-sequitor if you understand what g is. And know it's
>>> value.
>>
>>
>>
>> Yes. For some reason, you think g=1. I have no idea what you think g
>> is, though.
>>
>>> It's also not a non-sequitor if you know that multiplication by a
>>> constant is.
>>>
>>> It's not a non-sequitor if you know that force is often expressed in
>>> kilograms (or tonnes). More accurately, kilogram-force or kilopond
>>> but more commonly just kilogram. If it's good enough for Dassault
>>> Mirage, it's good enough for me.
>>> http://www.sengpielaudio.com/ConvForce.htm
>>>
>>> It's not a non-sequitor if you know that multiplying a scalar by a
>>> vector gives you a vector.
>>> "You are pressing down with 100kg". "Down" is a vector.
>>
>>
>>
>> "Down" has no magnitude therefore "down" is not a vector.
>
>
> You probably also think 0 is not a scalar.
Er, ok. I have no idea why you think "down" is a vector.
> Below you wrote F= 978.38 newtons. F is a vector where is the direction?
978.38 newtons in the direction of gravity's pull, or pushing up against
the chair. Pick whichever you prefer. However, there is also a force of
-978.38 newtons. You might notice this because you are not accelerating
at the rate of 9.8 m/s^2.
>>> It's only a non-sequitor if you want to distract from the fact that
>>> 5yen is inventing magical vectors to satisfy a highschool level
>>> mis-understanding of classical physics. Much like your highschool
>>> mis-understanding of fluid dynamics.
>>>
>>> It doesn't matter in this example anyway because mass *is* force.
>>
>>
>>
>> No, mass is not force.
>
>
> You stopped reading too soon.
>
>>
>>> Gravity is the property of mass and can be defined completely without
>>> any other reference.
Yes, gravity is a property of mass. This is quite a different thing from
saying "mass is force".
>>> The acceleration of gravity is also completely irrelevant. The force
>>> exterted between our 100kg 5yen and earth is derived by this formula
>>> F=6.67x10^-11 * m1 * m2 / r^2
>>> where m1=100,000 and m2 is the mass of the earth (in grams), r is
>>> distance. As you can see chairs have nothing to do with it.
>>
>>
>>
>> Actually, in that equation, the masses for "m" are in kilograms. I'll
>> show you how it works.
>>
>> Remember when I said that gravity's pulls with a force of 980 newtons
>> on a person with a mass of 100 kg?
>>
>> F = (6.67e-11)(100)(5.97e24)/(6.38e6)^2
>>
>> F = 3.982e16/4.07e13
>>
>> F= 978.38 newtons
>
>
> Very good.
A shame that you thought m1 and m2 were in grams.
> How is that expressed as a force vector? Now you need to read
> Newton's law of gravity to apply that to get past your highschool
> physics. Here is a good quote:
>
> "Certainly gravity is a force which exists between the Earth and the
> objects which are near it. As you stand upon the Earth, you experience
> this force. We have become accustomed to calling it the force of gravity
> and have even represented it by the symbol Fgrav. Most students of
> physics progress at least to this level of sophistication concerning the
> notion of gravity."
>
> Gowen seems to have got to that stage, now he just needs to try to work
> out what a chair has got to do with the attraction of earth and him.
I never said a chair had anything to do with it. I simply said that the
chair a person at rest is sitting upon exerts a force equal and opposite
to that of gravity.
> The
> first step would be to realise that his primitive concept of 3
> dimensional vectors can't describe the mutal attraction of two bodies.
Alrighty then. Why did you take out sci.physics, by the way? Surely they
could set you straight.
- Kevin
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