고체역학 (Gere) — Torsion: Problem 3.2-1

3.2-1 A circular tube is subjected to torque $T$ at its ends. The resulting maximum shear strain in the tube is 0.005. Calculate the minimum shear strain in the tube and the shear strain at the median line of the tube section. (From the image: Outer diameter $d_2 = 75\text{ mm}$, Inner diameter $d_1 = 63\text{ mm}$)