Re: Newtons Mechanics only valid from nonaccelerating frame of reference?

In article <dquiet$cpp$1@xxxxxxxxxxxxxxxxxxxxxxxx>, glhansen@xxxxxxxxxxxxxxxxxxxxx (Gregory L. Hansen) writes:
>In article <20060122054035.A97811@xxxxxxxxxxxxx>,
>Timo Nieminen <uqtniemi@xxxxxxxxxxxxxxxxx> wrote:
>>On Fri, 20 Jan 2006 jmfbahciv@xxxxxxx wrote:
>>
>>> Timo Nieminen <timo@xxxxxxxxxxxxxxxxx> wrote:
>>>>
>>>> You can introduce fictitious forces (eg centrifugal force, Coriolis force)
>>>> so that you can continue to use Newton's laws.
>>>
>>> Would people understand more if you called the fictitious forces
>>> fudge factors?
>>
>>A minority might; I don't think most would.
>>
>>There's a fundamental different between the non-inertial frame and your
>>examples: in the non-inertial frame, one is seeing exactly the same events
>>as one sees in an inertial frame; they just look different. Your examples
>>are of things that really are different.
>>
>>The error due to the end of a tape is a real error; needing to aim a gun
>>differently due to the sights not being perfectly adjusted is real.
>>Fictitious forces, OTOH, do not exist; that's the point of the name. There
>>is _no_ centrifugal force. But it can be useful to pretend that there is.
>
>I strongly disagree with statements like there are no centrifugal forces
>or there are no coriolis forces, etc. The smug academic might say "It's
>really a cen-TRIP-etal force causing the object to accelerate." But who
>are they to declare that someone in an accelerated reference frame can't
>declare himself to be at rest? What the term "fictitious force" is really
>saying is that only inertial reference frames are real-- accelerated
>reference frames are as fictitious as the forces within them. But the
>choice of reference frame is arbitrary, and inertial is no more or less
>real than anything else. If you are at rest in an accelerated reference
>frame then the force required to hold an object still is very real.
>Release a ball and you are as entitled to say it accelerates away as the
>academic is to say that it finally stops accelerating and starts going in
>a straight line. Whose straight line is that?
>--
Yes, I'll agree with this. That's why I find the very name
"fictitious" disagreable (I'll note that Landau, in his "Mechanics",
doesn't use the term "fictitious forces" but "inertial forces").
True, in a properly chosen frame of reference they disappear. But
then, in the quadratic equatoin

a*x^2 + b*x + c = 0

the middle (linear) term can always be made to disappear by an
appropriate transformation, and we don't refer to it as a "fictitious
term".

Mati Meron | "When you argue with a fool,
meron@xxxxxxxxxxxxxxxxx | chances are he is doing just the same"
.

Relevant Pages

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