The maximum shear stress (qmax) in a rectangular beam is A. 1.25 times the average B. 1.50 times the average C. 1.75 times the average D. 2.0 times the average

The correct answer is: The maximum shear stress (qmax) in a rectangular beam is 1.50 times the average.

The shear stress in a beam is the force per unit area that acts parallel to the cross-section of the beam. The average shear stress is equal to the shear force divided by the area of the cross-section. The maximum shear stress occurs at the neutral axis of the beam, which is the axis that passes through the centroid of the cross-section. The maximum shear stress is equal to 1.5 times the average shear stress.

The following is a brief explanation of each option:

• Option A: 1.25 times the average. This is incorrect because the maximum shear stress is not equal to 1.25 times the average shear stress.
• Option B: 1.50 times the average. This is the correct answer because the maximum shear stress is equal to 1.5 times the average shear stress.
• Option C: 1.75 times the average. This is incorrect because the maximum shear stress is not equal to 1.75 times the average shear stress.
• Option D: 2.0 times the average. This is incorrect because the maximum shear stress is not equal to 2.0 times the average shear stress.