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Re: centrifugal force



At 08:16 PM 4/30/98 -0400, you wrote:

Why are we making a mountain out of this? The definition: "An inertial
frame is one in which the law of inertia holds" is circular! How do you
know if the law of inertia holds? You have to decide whether a body is
force free. How do you do that? Well if it doesn't accelerate? But then
you are assuming that you are in an inertial frame!

It was clear many decades ago that there is no absolute way to decide
whether you are in an inertial frame.

Yes. That is right. There is no way to get hold of an inertial frame.
But since we have discovered Newton's Laws by experiments on earth and
we could not have done so if earth were not atleast aprroximately
inertial, we postulate an inertial frame in which Newton's Laws hold
absolutely.We explain deviations of motions of objects on earth from
the ideal behaviour to be due to the earth being only approximately
inertial.

regards,

sarma.