1. The problem statement, all variables and given/known data "A 1250 kg slipper hippo slides down a mud covered hill inclined at an angle of 18 degrees to the horizontal. A) If the coefficient of friction is 0.0900, what force of friction impedes the hippo's motion down the hill? B) If the hill were steeper, how would this affect the coefficient of sliding friction?" 2. Relevant equations mg x sin(θ) mg x cos(θ) ƩF = ma μmg x sin(θ) μmg x cos(θ) 3. The attempt at a solution Our professor/teacher taught us by just using mg x sin(θ) and plugging in the values. Someone in the class used the formula μmg x sin(θ) from a physics book and got a completely different answer than the teacher. So my main question is: Does coefficient of friction affect the force of friction and if so, would I use μmg x sin(θ)? I am confused because if the coefficient of friction doesn't affect the force of friction why bother list it in the problem.