Explain what is shearing stress?

Two solid steel shafts (G = 77.2 GPa) are connected to a coupling disk B and to fixed supports at A and C. For the loading shown, determine (a) the reaction at each support, (b) the maximum shearing stress in shaft AB, (c) the maximum shearing stress in shaft BC.

 Two solid steel shafts (G 77.2 GPa) are connected to a coupling disk Band Problem 3.56 to fixed supports at A and C. For the loading shown, determine

(a) the reaction at each support,

(b)the maximum shearing stress in shaft AB,

(c)the maximum shearing stress in the shaft BC

Which fluid does not experience shearing stress during flow?