Does rotational motion affect the translational motion?

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Discussion Overview

The discussion revolves around the relationship between rotational motion and translational motion, specifically whether the effects of rotational motion (represented by the Coriolis force) can be observed in an inertial frame. The scope includes theoretical considerations of motion in different reference frames.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant describes a scenario involving a flying object with both translational and rotational motion, introducing the concept of a Coriolis-like force (ω×ν) in the body frame.
  • Another participant argues that in the body frame, every point is at rest with respect to the rotating coordinates, thus claiming there is no Coriolis force present in that frame.
  • A third participant provides an equation related to the velocity components and rotation rates in the body-fixed frame, suggesting a mathematical representation of the motion.
  • One participant asserts that no equivalent force of ω×ν exists in the inertial frame, stating that inertial forces are exclusive to non-inertial frames.

Areas of Agreement / Disagreement

Participants express differing views on the existence of the Coriolis force in the inertial frame, indicating a lack of consensus on this topic.

Contextual Notes

Participants reference specific conditions related to the frames of reference and the nature of forces, but these assumptions and definitions remain unresolved within the discussion.

Avijit
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A flying object is moving in 3D space having translational velocity and the object is also rotating. Consider a body frame (xb-yb-zb) attached to the C.G of the moving body. Hence the body attached frame is also translating and rotating (as the object is flying) with respect to a fixed inertial frame. The inertial frame(X-Y-Z) is attached and fixed at some specific location on ground(earth). Due to the effect of both translation and rotation a Coriolis kind of force (rotational velocity cross translational velocity) ω×ν will exist in body attached frame (xb-yb-zb). Here ω: Rotational velocity of the flying object, v: velocity of the object represented in body attached frame (xb-yb-zb).

I would like to know :
Does any equivalent force of ω×ν will exist in the inertial frame? In other words, using the frame transformation (from body attached frame to inertial frame) can we realize the ω×ν effect in inertial frame?
 
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In your described scenario, every point in the body is at rest with respect to the rotating coordinates, so there's no Coriolis force. Remember the rotating reference frame is attached to the center of mass of the object, so there's no translational velocity in that frame.
 
upload_2016-12-15_7-41-16.png
here is the equation in body fixed frame
where U V W are velocity component of moving body represented in body frame. P Q R are body rotation rates in respective direction
 
Last edited:
Avijit said:
Does any equivalent force of ω×ν will exist in the inertial frame?
No, inertial forces exist only in non-inertial frames.
 

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