Question

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 10 times a person's weight. According to one set of experiments, the average area of the Achilles tendon is 77.9 mm2 , its average length is 25 cm , and its average Young's modulus is 1474 MPa .

part a for tensile stress is 7.08x10^7 Pa

b. If we model the tendon as a spring, what is its force constant?

K=f/x = tensile strength (area) / .048(.025)

7.08x10^7 ( 77.9x10.3)/ .048(.025)

=4.6x10^8 ( I am geting this wrong and if someone could see what i am doing wrong i would aperciate it.)

c. If a 75 kg sprinter exerts a force of 10 times his weight on his Achilles tendon, by how much will it stretch?

Answer 1