Topic: Strength of Materials
A 0.2 mm thick strip is bent and laid over a frictionless pulley of 25 mm diameter. If E = 100 GPa, the maximum stress in the strip is
- A. 100 MPa
- B. 200 MPa
- C. 400 MPa
- D. 800 MPa
Answer: D. 800 MPa
Explanation: The bending stress is sigma = E * y / R. Here, y is half the thickness of the strip (0.2/2 = 0.1 mm). The radius of the neutral axis R = D/2 + y = 25/2 + 0.1 = 12.6 mm (approximated as 12.5 mm for calculation matching options). sigma = 100,000 MPa * (0.1 / 12.5) = 800 MPa.