[amp_mcq option1=”minimum” option2=”maximum” option3=”negative value” option4=”could be any value” correct=”option1″]
The correct answer is A. minimum.
The shear stress is the force per unit area acting parallel to the surface of a fluid. It is caused by the relative motion of the fluid particles. The shear stress is zero at the center line of a pipe flowing under pressure because there is no relative motion of the fluid particles at the center line.
Option B is incorrect because the shear stress is minimum at the center line of a pipe flowing under pressure.
Option C is incorrect because the shear stress cannot be a negative value.
Option D is incorrect because the shear stress is not any value. It is a specific value that is determined by the fluid properties and the flow conditions.