## College Physics (4th Edition)

(a) The spring constant of the tendon is $3.2\times 10^5~N/m$ (b) The muscle did $20~J$ of work stretching the tendon.
(a) We can find the spring constant of the tendon: $k = \frac{\Delta F}{\Delta x} = \frac{4800~N-3200~N}{0.0050~m} = 3.2\times 10^5~N/m$ The spring constant of the tendon is $3.2\times 10^5~N/m$ (b) We can find the average force required to stretch the tendon: $F_{ave} = \frac{4800~N+3200~N}{2} = 4000~N$ We can find the work required to stretch the tendon: $Work = F_{ave}~d = (4000~N)(0.0050~m) = 20~J$ The muscle did $20~J$ of work stretching the tendon.