When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be
A. $$\frac{{4{\text{F}}}}{{\pi {{\text{d}}^2}}}$$
B. $$\frac{{{\text{6F}}}}{{\pi {{\text{d}}^2}}}$$
C. $$\frac{{{\text{8F}}}}{{\pi {{\text{d}}^2}}}$$
D. $$\frac{{{\text{16F}}}}{{3\pi {{\text{d}}^2}}}$$
Answer: Option D

For circle,
Shear Stress = FAy/It.
= F* (((pi/8)*d^2)*(2d/3pi))/((pi/64)*d^4*d).
= 16F/3pid^2.