A paper clip is made of wire 0.7 mm in diameter. If the original material from which the wire is made is a rod 25 mm in diameter, calculate the longitudinal engineering and true strains that the wire has undergone during processing.

(b) The engineering yield strength of a copper alloy is 23.9 ksi and the modulus of elasticity is 16x106 psi. Estimate the engineering strain just before yield and the corresponding true strain. Are you surprised with the result in (b)