Question

The elastic energy stored in your tendons can contribute up to 35%% of your energy needs when running. Sports scientists find that (on average) the knee extensor tendons in sprinters stretch 41 mmmm while those of nonathletes stretch only 33 mmmm . The spring constant of the tendon is the same for both groups, 33 N/mmN/mm. Part A What is the difference in maximum stored energy between the sprinters and the nonathletes

Answer 1

11.16 J

Step-by-step explanation:

Elastic energy (E) stored in the tendon is given by 1/2ke^2

SPRINTERS

k = 31N/mm = 31N/mm × 1000mm/1m = 31,000N/m

e = 41mm = 41mm × 1m/1000mm = 0.041m

E = 1/2 × 31,000 × 0.041^2 = 26.06J

NON-ATHLETES

k = 31,000N/m

e = 31mm = 31mm × 1m/1000 = 0.031m

E = 1/2 × 31,000 × 0.031^2 = 14.90 J

Difference = 26.06 J - 14.90 J = 11.16 J