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Old 04-10-2018, 03:06 PM   #22 (permalink)
cr45
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Quote:
Originally Posted by RedDevil View Post
Inertia is not linear but quadratic to speed.
It takes 0.5 Joule to speed up that kilogram to 1 meter per second, it takes 2 Joule for 2 m/s, 4.5 for 3 m/s, etc.
Inertia, if you mean the contained energy, in your formula is not mass * radius but mass * (radius ^ 2) / 2.

And remember, only the speed matters, not the direction; whether it is straight, turning slowly in a big circle or fast in a tiny circle is indifferent. Only its speed matters.
You appear to be confusing the term "inertia" with "kinetic energy".

A mass M moving at a velocity V has a kinetic energy of 0.5 * M * V * V.

This however is not inertia.

Inertia is a measure of a body's resistance to changes in velocity.

It can be found from Newton's second law F = M * A and thus M = F / A

As there is no gravity in space, astronauts determine their mass (inertia) in a special device that applies a force and the rate of acceleration is measured. The rearranged Newtons 2nd equation is then used to calculate their mass (inertia).
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