The figure shows two thin-walled circular cross-sections with radius a and wall thickness t
a) Determine the torsion stiffness parameter Kclosed of the closed cross-section in Fig. a).
b) Determine the torsion stiffness parameter Kopen of the open cross-section in Fig. b).
c) Determine and comment on the torsion stiff-ness ratio Kopen/Kclosed.
![1973_d8baab8e-4fd8-4213-a6d2-2928aaf0a9e9.png](https://secure.tutorsglobe.com/CMSImages/1973_d8baab8e-4fd8-4213-a6d2-2928aaf0a9e9.png)