Moment of inertia of 2 uniform thin rods

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SUMMARY

The discussion focuses on calculating the moment of inertia of two uniform thin rods about a specific axis (point A) using the parallel axis theorem. The center of mass (COM) for the top rod is located at y = 0.5L, while the COM for the bottom rod is at x = 0.5L. The moment of inertia is calculated with the formula I = (1/12)ml² + md², where d represents the distance between the center of mass and point A. The participants confirm the calculation of d for both rods, ensuring accurate application of the theorem.

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jisbon
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Homework Statement
Calculate the moment of inertia of 2 uniform thin rods about axis A where the figure belows shows the top view.
Relevant Equations
##I=\frac{1}{12}ml^2##
1571734403087.png


So to start off, what I will do find the center of mass of each of the rods. So for the top rod, COM is at where y= 0.5 L and COM of the rod at the bottom is at x = 0.5 L. From there, how do I proceed in finding the moment of inertia using parallel axis theorem? Do I simply treat:
##I =\frac{1}{12}ml^2+md^2##
Where d is the distance between the centre of mass and point A for each of the rods respectively? (Whereby d will be 0.5 L - 4/9 L for the bottom rod)

Thanks
 
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jisbon said:
Homework Statement: Calculate the moment of inertia of 2 uniform thin rods about axis A where the figure belows shows the top view.
Homework Equations: ##I=\frac{1}{12}ml^2##

View attachment 251651

So to start off, what I will do find the center of mass of each of the rods. So for the top rod, COM is at where y= 0.5 L and COM of the rod at the bottom is at x = 0.5 L. From there, how do I proceed in finding the moment of inertia using parallel axis theorem? Do I simply treat:
##I =\frac{1}{12}ml^2+md^2##
Where d is the distance between the centre of mass and point A for each of the rods respectively? (Whereby d will be 0.5 L - 4/9 L for the bottom rod)

Thanks
Yes. What will d be for the other rod?
 
haruspex said:
Yes. What will d be for the other rod?
Will it be ##\sqrt(({\frac{3}{9}L)}^2+(0.5L)^2)##?
 
Solved it. Thanks so much for your guidance 😄
 

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