Lets consider this: Imagine the situation where a disc is rolling and also spinning about a point on ground (rolling without slipping) if someone asks to tell whats the angular momentum of disc about COM ,why should we include both the orbital and spinning angular velocities angular momentum consideration, in com frame wouldnt both the $w_s$ and $w_o$ vanishes off ? Just imagine a person sitting on the COM of disc he will say he is observing no motion at all of the disc no spinning ,no translatory at all, so why does angular momentum about com is not zero? And why its just a translatory frame, why not both a translatory as well as rotatory frame? Why dont points rotate and just always translate?
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Newton's laws do not work in non-inertial reference frames. A constant velocity reference frame, which includes the COM frame, is inertial because its acceleration is zero. Spinning reference frames involve centripetal acceleration, and hence, are non-inertial.
answered Dec 13, 2021 at 16:10
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$\begingroup$ Oh so because of non-inertial (pseudo force) terms will come into effect if one considers the com frame to be rotatory as well as translatory , hence com is" just considered to be translatory frame by definition for easiness " ? Sir? And similarily any other point frame . $\endgroup$ Commented Dec 13, 2021 at 16:38
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$\begingroup$ Easiness to calculate things like angular momentum etc... $\endgroup$ Commented Dec 13, 2021 at 16:42
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