Calculating Moment of Inertia & Torque for a Rod on a Pivot

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Discussion Overview

The discussion revolves around calculating the moment of inertia and torque for a rod swinging on a pivot, specifically addressing the challenges of analyzing the system from different frames of reference (F.O.R). Participants explore the implications of using an accelerated frame of reference and the associated fictitious forces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant, Dweirdo, questions the validity of substituting angular acceleration from one frame of reference to another and seeks clarification on how to account for fictitious forces in an accelerated frame.
  • Another participant suggests that it is possible to use the same equations and refers to fictitious forces, indicating that there are resources available for further understanding.
  • Dweirdo asks for guidance on whether to use the concept of a rotating observer or rotating coordinate systems, expressing confusion about their equivalence.
  • There is a discussion about the symbol Ω, with participants clarifying that it represents angular velocity and expressing frustration over the complexity of terminology.

Areas of Agreement / Disagreement

The discussion reflects a lack of consensus on the application of equations across different frames of reference and the interpretation of terms related to angular motion. Participants express differing levels of understanding and comfort with the concepts involved.

Contextual Notes

Participants exhibit uncertainty regarding the application of fictitious forces and the appropriate frame of reference to use, highlighting potential limitations in their understanding of the underlying principles.

Who May Find This Useful

This discussion may be of interest to students and enthusiasts of physics, particularly those exploring dynamics, rotational motion, and the implications of different frames of reference in mechanics.

Dweirdo
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Hi

if i have let's say a rod swinging on a pivot, and i calculate the moment of inertia around the axis, which is the pivot, and i get the angular acceleration.
now let's say i want to the the same around the other end of the rod, but the thing is that in the lab F.O.R it is moving around the pivot, although in the F.O.R of the other end of the rod, the pivot moves around that end, so why can't i make the same equations, and substitute angular acceleration with the one that i got before, and then find the net torque,
i mean, because it's an accelerated f.O.R i need to be careful, and add some factious forces and stuff, so how do i deal with that?
thanks
Dweirdo
 
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Dweirdo said:
… why can't i make the same equations, and substitute angular acceleration with the one that i got before, and then find the net torque, i mean, because it's an accelerated f.O.R i need to be careful, and add some factious forces and stuff, so how do i deal with that?

Hi Dweirdo! :wink:

Yes, you can do that … see, for example, http://en.wikipedia.org/wiki/Fictitious_force :smile:
 
Hi Tim,and thanks
I've looked it p, but which one of these should i use in my case:
1)Rotating observer
2)Rotating coordinate systems

and what is this symbol:Ω?
thanks :)
Dweirdo
 
Dweirdo said:
… which one of these should i use in my case:
1)Rotating observer
2)Rotating coordinate systems

Theyr'e the same aren't they? :confused:

(and Ω is angular velocity)
 
idk they come up as 2 different sectors :P oh well
and why the hell they have to make things so complicated , omega should be angular velocitY! :P
thanks again,
dweirdo
 
never mind, silly question :(
 
Frame of reference-F.O.R :P
 
Ω

Dweirdo said:
and why the hell they have to make things so complicated , omega should be angular velocitY! :P

Hi Dweirdo! :smile:

Ω is capital ω … see http://en.wikipedia.org/wiki/Greek_alphabet :wink:

(that's partly why someone with a sense of humour made Ω the symbol for ohm! :biggrin:)
 
haha cool :) still omega sounds way smoother :P
i still think they just try to make things complicated :)
*goes to study greek alphabet* :DD
Dweirdo
 

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