- #1
swapnilp
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Consider a sphere constrained to roll on a rough FLAT HORIZONTAL surface. A book on classical mechanics says it requires 5 generalized co-ordinates to specify sphere's configuration: 2 for its centre of mass and 3 for its orientation.
I did not understand why 3 for orientation. I guess only 2 are needed: one altitude and one azimuth i.e. ## \theta## and ## \phi ##. Since radius is fixed, ## r ## is not needed.
So only 2+2 = 4 generalized co-ordinates are needed as per my understanding.
I assume book is right. So what is wrong in my understanding ?
I did not understand why 3 for orientation. I guess only 2 are needed: one altitude and one azimuth i.e. ## \theta## and ## \phi ##. Since radius is fixed, ## r ## is not needed.
So only 2+2 = 4 generalized co-ordinates are needed as per my understanding.
I assume book is right. So what is wrong in my understanding ?
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