Rotational speed at axis of rotation?

In summary, the conversation discusses the question of whether only the tangential speed is zero for a point at the axis of rotation in a rotating solid. It is mentioned that the behavior of solids as a whole can affect this, especially for very small points like atoms. It is also noted that the tangential speed changes as you approach the center, but the angular velocity remains the same for all points except for those smaller than an atom.
  • #1
ViolentCorpse
190
1
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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  • #2
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
 
  • #3
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:
 

FAQ: Rotational speed at axis of rotation?

1. What is rotational speed at the axis of rotation?

The rotational speed at the axis of rotation is the speed at which an object is rotating around its central axis. It is usually measured in rotations per minute (RPM) or radians per second (rad/s).

2. How is rotational speed at the axis of rotation calculated?

The rotational speed at the axis of rotation can be calculated by dividing the angular displacement by the time it takes for the object to complete one rotation. This can also be represented as the ratio of the circumference of the circle to the time it takes for the object to travel around it.

3. What factors affect the rotational speed at the axis of rotation?

The rotational speed at the axis of rotation can be affected by the mass, shape, and distribution of mass of the object. Other factors such as external forces and friction can also impact the rotational speed.

4. How does rotational speed at the axis of rotation relate to rotational inertia?

Rotational speed at the axis of rotation is directly proportional to the rotational inertia of an object. An object with a higher rotational inertia will require more torque to achieve the same rotational speed as an object with a lower rotational inertia.

5. Why is the rotational speed at the axis of rotation important in physics?

The rotational speed at the axis of rotation is important in physics because it helps us understand the motion and behavior of rotating objects. It is also a key factor in many practical applications, such as designing machinery and calculating the stability of structures.

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