## Fundamentals of Physics Extended (10th Edition)

$\mu_k=0.61 N$
Force of friction and normal reaction are mutually related as follows: $f=\mu_k F_N$ where $\mu_K$ is coefficient of kinetic friction We also know that $F_N=mg$ (weight of the baseball player ) Hence $f=\mu_kmg$ or $\mu_k=\frac{f}{mg}$ Substituting the values and solving: $\mu_k=\frac{470}{(79)(9.8)}$ $\mu_k=0.61 N$