Question: What is the shear stress in a circular shaft subjected to a torque of 500 Nm and a diameter of 50 mm?

Options:

1. 15.92 MPa
2. 31.84 MPa
3. 63.68 MPa
4. 79.58 MPa

Correct Answer: 31.84 MPa

Solution:

Shear stress τ = (T * r) / J, where J = (π/32) * d^4. For d = 0.05 m, J = (π/32) * (0.05)⁴ = 4.91e-9 m^4. τ = (500 * 0.025) / 4.91e-9 = 31.84 MPa.