Calculating Moment of Inertia for a Curved Rod with Respect to a Specific Axis

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SUMMARY

The discussion focuses on calculating the moment of inertia \( I_{x'x'} \) for a thin, homogeneous curved rod with radius of curvature \( R \) and mass \( m \), specifically about the axis passing through the center of mass \( G \). The relevant equation utilized is Steiner's theorem: \( I_{xx} = I_{x'x'} + m y^2_G \). Participants suggest using the parallel and perpendicular axis theorems to simplify the calculation, indicating that finding \( I_{Oz} \) and converting it to \( I_x \) may be a viable approach before shifting to the desired axis.

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  • Understanding of moment of inertia concepts
  • Familiarity with Steiner's theorem
  • Knowledge of parallel and perpendicular axis theorems
  • Basic principles of rigid body dynamics
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  • Learn about the parallel axis theorem and its implications
  • Explore the perpendicular axis theorem for planar bodies
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Iqish
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Homework Statement
A thin, homogeneous, curved rod with
the radius of curvature 𝑅 and mass 𝑚 are in
𝑥𝑦 plane. Determine the moment of inertia,
𝐼𝑥'𝑥 ', with respect to the 𝑥 'axis, which goes
through the body's center of mass G
Relevant Equations
Steiners sats:𝐼𝑥𝑥 = 𝐼𝑥′𝑥′ + 𝑚𝑦^2𝐺
Given:Thin, homogeneous, curved rod with radius of curvature 𝑅 See figure to the down.
7m2HF.png

Find: The moment of inertia 𝐼𝑥′𝑥 ′ with respect to 𝑥′- the axis passing through the center of mass (point 𝐺).
Can someone who can help me ?
 
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Iqish said:
Homework Statement:: A thin, homogeneous, curved rod with
the radius of curvature 𝑅 and mass 𝑚 are in
𝑥𝑦 plane. Determine the moment of inertia,
𝐼𝑥'𝑥 ', with respect to the 𝑥 'axis, which goes
through the body's center of mass G
Relevant Equations:: Steiners sats:𝐼𝑥𝑥 = 𝐼𝑥′𝑥′ + 𝑚𝑦^2𝐺

Given:Thin, homogeneous, curved rod with radius of curvature 𝑅 See figure to the down.
View attachment 258878
Find: The moment of inertia 𝐼𝑥′𝑥 ′ with respect to 𝑥′- the axis passing through the center of mass (point 𝐺).
Can someone who can help me ?

Have you learned about the parallel and perpendicular axis theorems?

Just an initial thought that I have on this. So it looks quite difficult to actually calculate the moment of inertia about the required axis, so it suggests to me that we will be shifting it to that axis (via parallel axis theorem). Perhaps, we can find I_{Oz} (out of the page) , turn that into I_{x} via perpendicular axis theorem and then shift it to the required axis (would require us to know the location of G, but that seems easier to find than calculating about that axis. Otherwise, maybe we find I_{x} and then shift?

(Note, we would be 'reverse' shifting it as the parallel axis theorem is defined for an axis relative to centroid axis, would just mean that we subtract the m d^2, rather than add it)
 

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