# The Achilles tendon force

The Achilles tendon force of $F_t=650$ N is mobilized when the man tries to stand on his toes. As this is done, each of his feet is subjected to a reactive force of $N_f=400$ N. Determine the resultant moment of $F_t$ and $N_f$ about the ankle joint A.

Image from: Hibbeler, R. C., S. C. Fan, Kai Beng. Yap, and Peter Schiavone. Statics: Mechanics for Engineers. Singapore: Pearson, 2013.

#### Solution:

Let us write a moment equation about point A. We will assume clockwise moments to be positive.

$\circlearrowright M_A=(650\cos5^0)(0.065)-(400)(0.1)$

$M_A=2.09\,\text{N}\cdot\text{m}\circlearrowright\text{(Clockwise)}$