## Essential University Physics: Volume 1 (3rd Edition)

$F_t = \frac{\mu_k mg}{cos\theta + \mu_k sin \theta}$
We first find the x and y components of each of the forces: $F_n = mg - F_tsin\theta$ and $F_tcos\theta- \mu_k F_n= 0$ Using substitution, we find: $F_tcos\theta- \mu_k F_n= 0$ $F_tcos\theta- \mu_k (mg - F_tsin\theta)= 0$ $F_t = \frac{\mu_k mg}{cos\theta + \mu_k sin \theta}$