Angular acceleration x radius= Acceleration of center of mass ?

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Discussion Overview

The discussion revolves around the relationship between angular acceleration, radius, and the acceleration of the center of mass in rotating bodies. Participants explore the implications of angular acceleration in both translating and non-translating contexts, as well as the definitions and relationships between tangential acceleration and linear acceleration of points on a rotating body.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that the equation (angular acceleration x radius) relates to the linear acceleration of a point on the body, specifically its tangential velocity with respect to the center of mass.
  • Others clarify that the correct relationship is atan = αr, where atan is the tangential acceleration of a point, α is the angular acceleration, and r is the distance from the point to the center of rotation.
  • One participant notes that the relationship acm = αr is a constraint that applies when a body is both rotating and translating, using the example of a sphere rolling without slipping.
  • There are corrections regarding terminology, with some participants suggesting that "center of mass" should be replaced with "center of rotation" in certain contexts.
  • Disagreement exists over the interpretation of how points move around the body and the validity of the speed equation R x α.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are multiple competing views regarding the relationships and definitions involved in the discussion of angular acceleration and linear acceleration in rotating bodies.

Contextual Notes

There are unresolved issues regarding the definitions of terms like "center of mass" versus "center of rotation," and the applicability of certain relationships under different conditions of motion.

AakashPandita
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For a rotating body,
(angular acceleration x radius)= Acceleration of center of mass ?

But a rotating body can have angular acc. even if it is not translating. what is wrong?
 
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no no no... angular acc. x radius = the linear acc. of a point on the body , ie the tangential velociti of that point with respect to the centre of mass
 
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the point is moving around the body with a speed= R x α
where α= angular acceleration
 
Hi Aakash...

The correct relationship for a point on a rotating body is

atan = αr where ,

atan=tangential acceleration of the point with respect to center of the axis

α = angular acceleration of the rotating body

r= distance between the point and the center of the axis

AakashPandita said:
For a rotating body,
(angular acceleration x radius)= Acceleration of center of mass ?

But a rotating body can have angular acc. even if it is not translating. what is wrong?

The relationship acm = αr is a constraint which is sometimes obtained in cases when a body is rotating as well as translating.

For eg. a sphere rolling without slipping on floor .
 
Tanya Sharma said:
Hi Aakash...

The correct relationship for a point on a rotating body is

atan = αr where ,

atan=tangential acceleration of the point with respect to center of the axis

α = angular acceleration of the rotating body

r= distance between the point and the center of the axis



The relationship acm = αr is a constraint which is sometimes obtained in cases when a body is rotating as well as translating.

For eg. a sphere rolling without slipping on floor .

i have told the same...:cool:
 
Kishlay said:
i have told the same...:cool:

Your language is sloppy and inaccurate .

Kishlay said:
no no no... angular acc. x radius = the linear acc. of a point on the body , ie the tangential velociti of that point with respect to the centre of mass

The item in red should be acceleration.

Again ,instead of center of mass,you should have used center of rotation.

Kishlay said:
the point is moving around the body with a speed= R x α
where α= angular acceleration

That doesn't make any sense . Neither the point is moving around the body ,nor is speed equal to R x α
 
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thanks.
 

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