Orbital vs. Angular Speed: What's the Difference in Circular Motion?

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Discussion Overview

The discussion centers on the distinction between orbital speed and angular speed in the context of circular motion, particularly as it pertains to objects or stars orbiting one another. The scope includes conceptual clarification and technical explanation of these terms.

Discussion Character

  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants propose that orbital speed refers to the speed transverse to the orbit, measured in units like m/s, calculated as the circumference of the orbit divided by the orbital period.
  • Others argue that angular speed is defined as the angle traveled per unit time, with units like rad/s, and for a circular orbit, it is expressed as 2π divided by the orbital period.
  • A participant notes that orbital speed and angular speed are related through the radius of the orbit, stating that for a circular orbit of radius r, orbital speed equals r times angular speed.
  • A caveat is mentioned regarding the use of these terms, suggesting that speakers may use them in different contexts, such as referring to orbit versus spin, which could lead to confusion.

Areas of Agreement / Disagreement

Participants present differing perspectives on the definitions and implications of orbital speed and angular speed, indicating that there is no consensus on the nuances of these terms.

Contextual Notes

There are potential limitations in understanding due to varying contexts in which the terms are used, as well as the possibility of confusion arising from different interpretations of the same concepts.

alybtd
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Is there a difference between orbital speed and angular speed when an object or star is considered to be in a circular motion around another?
 
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Welcome, might want to post your Q in the proper area.. Welcome anyway..:redface:
 
Electron Spin said:
Welcome, might want to post your Q in the proper area.. Welcome anyway..:redface:
Thanks!
Where should I ask that?
 
alybtd said:
Where should I ask that?

Depends if its a homework question or a general question. Respectively, homework or astronomy sections would work.

I would do a search here. I am sure this question has been asked about 3 million times! :smile:

Electron Spin
 
Welcome to PF!

alybtd said:
Thanks!
Where should I ask that?

I've moved the thread to the General Physics forum.
 
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Electron Spin said:
Depends if its a homework question or a general question. Respectively, homework or astronomy sections would work.

I would do a search here. I am sure this question has been asked about 3 million times! :smile:

Electron Spin

Thank you! I kinda found a way to figure it out and I found the right answer to what I was looking for, so yeah thanks!
 
Drakkith said:
Welcome to PF!
I've moved the thread to the General Physics forum.

Thank you!
 
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alybtd said:
Is there a difference between orbital speed and angular speed when an object or star is considered to be in a circular motion around another?

- Orbital speed means the speed transverse to the orbit. It is speed in the normal usage: distance traveled per unit time. It has units like m/s. For a circular orbit it is the circumference over the orbital period.
- angular speed differs in that it is the angle traveled per unit time. It has units like rad/s. For a circular orbit it is 2 π / the orbital period. Note: Since it is "transverse to the orbit" the direction at any point in time is well defined and this is often called orbital velocity.

The two are related by the radius of the orbit. For a circular orbit of radius r
Orbital speed = r * angular speed.

Caveat: if you are hearing both these phrases be careful that the speaker is using them both in reference to the same rotational motion. They might be using one in reference to the orbit and the other in reference to the spin or something like that.
 

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