514 A 100long surveyors steel tape with a crosssectional are

5.14 A 100\'-long surveyor\'s steel tape with a cross-sectional area of 0.006 sq. in. must be stretched with a pull of 16 pounds when in use. If the modulus of elasticity of this steel is E=30,000 ksi, (a) what is the total elongation in the 100 ft. tape and (b) what unit tensile stress is produced by the pull?

Solution

a) total elongation in the 100 ft. tape:

             S = PL/AE

                = 16(100 * 12)/0.006(30 * 10^4)

                = 19,200/180000

                = 0.1067\'

b) unit tensile stress:

    f = P/A

      = 16/0.006

       = 2666.67/1000

      = 2.667 psi