Chapter 1, Problem 1.8P

Suppose we know little about the strength of materials but are told that the bending stress s in a beam is proportionai to the beam half-thickness y and also depends on the bending moment M and the beam area moment of inertia 1. We also learn that, fur the particular case M = 2900 in · lbf, y = 1.5 in, and I = 0.4 in⁴, the predicted stress is 75 MPa. Using this information and dimensional reasoning only, find, to three significant figures, the only possible dimensionally homogeneous formula $\sigma$ = yf(M,I).