Ok, here's the problem that I am working on now. Sarah is walking at a speed of 1.5m/s when she accidentally slips on a patch of ice whose coefficient of kinetic friction is 0.060. If Sarah has a mass of 40.0 kg, how long before she comes to a stop on the ice? I'm stuck because I don't know which equation to use to solve for time or displacement. Each equation that I have has both variables in it. Also, where does the coefficient of kinetic friction factor into the equation. I solved for the normal force, and force of friction, but I still ended up in a dead end.