$2\mathrm{.}35$ Consider the gear$-$shaft system shown. Shafts $AB$ and $CD$ are both hollow with outside diameter $d_o=75mm$ and inside diameter $d_i=45mm.$ If the torque $Q=10kN*m,$ determine the maximum shearing stress in the shafts. Let $r_1=125mm$ and $r_2=300mm.$ Assume frictionless bearings.

$($Problems $2\mathrm{.}35$ and $2\mathrm{.}36)$