Rotational speed at axis of rotation?

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SUMMARY

The discussion centers on the concept of rotational speed at the axis of rotation in a solid body. It is established that while the tangential speed of a point at the axis of rotation is zero, the angular velocity remains constant across all points in the solid. The conversation highlights the distinction between tangential speed and angular velocity, emphasizing that the latter does not change regardless of proximity to the axis. The nuances of point size relative to atomic scale are also acknowledged, but they do not alter the fundamental principles of rotational motion.

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  • Knowledge of angular velocity and tangential speed
  • Familiarity with solid mechanics
  • Basic physics principles related to motion
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  • Explore the implications of point size on rotational dynamics
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ViolentCorpse
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Hello everyone!

This is probably the stupidest question that I've come up with, and I'm a little embarrassed asking it, but here goes:

Is it only the tangential speed that is zero of a point at the axis of rotation in a rotating solid? If not, then I don't understand how the rotational speed of a point in a rotating solid exactly at the axis of rotation could be zero unless it is somehow detached from the rest of the whole solid. I mean solids behave all-in-one-piece right? So it has to be rotating with the rest of it? :confused:
 
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There is the tricky problem of how small the point is or how close you can get to the centre. For example if the point you refer to is much much smaller than an atom issues such as "solids behave all-in-one-piece right" become irrelevant. At the same time if it's not zero size then it behaves like any other size point.

Consider how these two change as you approach the centre..

The angular velocity (degrees or radians/second)
The tangential speed
 
CWatters said:
For example if the point you refer to is much much smaller than an atom issues such as "solids behave all-in-one-piece right" become irrelevant.
That made me chuckle. :biggrin:

Consider how these two change as you approach the centre..

The angular velocity (degrees or radians/second)
The tangential speed
The tangential speed changes, but the angular velocity is the same for all points, I think. (except for the one smaller than an atom, as you mentioned)

Thank you very much for your help. I appreciate it. :smile:
 

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