Suppose we know little about the strength of materials but are told that the bending

Chapter 1, Problem p1.8

(choose chapter or problem)

Suppose we know little about the strength of materials but are told that the bending stress in a beam is proportional to the beam half-thickness y and also depends on the bending moment M and the beam area moment of inertia I . We also learn that, for the particular case M 5 2900 in lbf, y 5 1.5 in, and I 5 0.4 in 4 , the predicted stress is 75 MPa. Using this information and dimensional reasoning only, fi nd, to three signifi cant fi gures, the only possible dimensionally homogeneous formula 5 y f ( M , I ).