A laminated wood beam is built up by gluing together three 2-in.-by-4-in. members to form...

A laminated wood beam is built up by gluing together three 2-in.-by-4-in. members to form a solid beam 4-in.-by-6-in. in cross section, as shown. The allowable shear stress in the glued joints is 60 psi. The beam is a 3-ft-long cantilever with a load P applied at its free end. Neglecting the weight of the beam:

Problem

(a) Calculate the maximum allowable load P that can be applied at the free end.

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(b) Calculate the maximum bending stress in the beam.