Prob. 2.3-10. A rod AB, whose unstretched length is L., is

originally oriented an angle counterclockwise from the

+x axis. (a) If the rod is free to rotate about a fixed pin at

A, what is the extensional strain in the rod when end B

moves a distance u in the +x direction to point B*? Express

your answer in terms of the displacement u, the original

length L, and the original angle 8. (b) Simplify the answer

you obtained for Part (a), obtaining a small-displacement

approximation that is valid if u L. (Note: This result will

be used in Section 3.10.)

A

P2.3-10

B