How Do You Calculate Geometric Buckling for Cylinders and Spheres?

[stressedphysstudent]

Mentor note: Thread moved from a different forum section, so missing the homework template.
I'm very confused about the attached questions on geometric buckling of a cylinder and a sphere.

For this question I'm not given a value for the extrapolated distances (for R' and H') so I simply put the bare units in. The second question asks me to use a volume calculated from the first question, but my units are in m^-1.

I'm basically very confused about this question and any help would be much appreciated!

 

[jedishrfu]

Not sure if this will help but here's a brief tutorial on it's derivation and use:

https://wikivisually.com/wiki/Geometric_and_material_buckling

and this old PF post from another student:

https://www.physicsforums.com/threads/clarifying-geometric-and-material-buckling.309007/

 

[jedishrfu]

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