By how much does a 65.0-kg mountain climber stretch her 0.800-cm diameter nylon rope when she hangs 35.0 m below a rock outcropping? Young's modulus for the nylon rope is 5×109N/m2.

Respuesta :

Explanation:

Expression for Young's modulus is represented as follows.

            Y = [tex]\frac{\text{shear stress}}{\text{shear strain}}[/tex]

               = [tex]\frac{\frac{F}{A}}{\frac{\Delta L}{L_{o}}}[/tex]

where,   Y = Young's modulus

              F = force which acts perpendicular to the surface

              A = area of the surface

          [tex]L_{o}[/tex] = original length of the rope

          [tex]\Delta L[/tex] = elongation in the rope

The given data is as follows.

          r = 0.008 m,   mass (m) = 65 kg,    g = 9.8 m/s

         S = [tex]5 \times 10^{9} N/m^{2}[/tex]

         [tex]L_{o}[/tex] = 35 m

Force perpendicular to the surface is calculated as follows.

                   F = mg

                     = [tex]65 kg \times 9.8 m/s[/tex]

                     = 637 N

and,     Area = [tex]\pi r^{2}[/tex]

                     = [tex]3.14 \times (0.008)^{2}[/tex]

                     = [tex]20.096 \times 10^{-5}[/tex]

Putting the given values into the above formula as follows.

        [tex]\Delta L = \frac{1}{Y} \times \frac{F}{A} \times L_{o}[/tex]

                    = [tex]\frac{1}{5 \times 10^{9}} \times \frac{637 N}{20.096 \times 10^{-5}} \times 35 m[/tex]

                     = [tex]221.879 \times 10^{-4}[/tex]

                     = [tex]2.21 \times 10^{-2} m[/tex]

Thus, we can conclude that by [tex]2.21 \times 10^{-2} m[/tex] does a 65.0 kg mountain climber stretch her 0.800 cm diameter nylon rope.