0

I want to describe a rotation, A is static, and B is rotating.

Should I say " B is rotating relative to A"

when A and B both rotating, and they are static relative to each other, what is a sentence or word?

is relative the word to describe the two relationship? or better one?

Improve this question
6
  • 1
    You might need B revolves around A. Rotate means turning on your own axis. The Earth rotates each day and revolves around the sun each year.
    – Yosef Baskin
    Commented Jul 4 at 10:24
  • If (1) A and B both rotating, but (2) they are static relative to each other, there's no need to mention the second fact anyway. If you didn't say they were rotating relative to each other, the default assumption is they're static relative to each other. Rotating is usually relative to the "static" frame of reference relative to the centre of the earth, but it could be relative to something moving relative to that (a bird, a plane, or Superman flying). Or relative to the sun, or the galaxy,...
    – FumbleFingers
    Commented Jul 4 at 11:48
  • Doesn't relativity posit that with two bodies in space one can only describe relative motion? With an arbitrary origin in space, things are different.
    – Edwin Ashworth
    Commented Jul 4 at 14:51
  • To say B is rotating relative to A does not describe the relative motion at all well. Relative to A, B might be rotating about an axis passing through A or not passing through A, as well as revolving about a possibly different axis. And the axis of rotation may itself be changing. It is simpler of course if they are rotating together.
    – Peter
    Commented Jul 4 at 15:02
  • Thank you all so much, I am sorry for my English ability, I didn't make it very clear, here is what I want to say, a watch has a plate and 3 watch hand, 1, how to word the watch hand rotate while the plate is static? 2, I know there is no this kind of watch, both plate and its hand rotate, but in this situation, plate and hand is relative static to each other. how to describe the two situation, mainly on the two parts movement?
    – cmabill
    Commented Jul 5 at 0:19

0

Reset to default

Browse other questions tagged or ask your own question.