## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

We can use the impulse-momentum theorem to find the time $t$ to travel from point A to point B. Note that the impulse $J$ is equal to $-F_f~t$, where $F_f$ is the magnitude of the force of friction exerted on the sled. $p_0+J = p_f$ $p_0-F_f~t = p_f$ $-F_f~t = p_f - p_0$ $-mg~\mu_k~t = m~(v_f-v_0)$ $t = \frac{(v_f-v_0)}{-g~\mu_k}$ $t = \frac{(5.0~m/s-8.0~m/s)}{-(9.80~m/s^2)(0.25)}$ $t = 1.2~s$ The sled takes 1.2 seconds to travel from point A to point B.