1. The problem statement, all variables and given/known data A 4.00 kg block starts from rest at the top of a 30° incline and slides a distance of 2.10 m down the incline in 1.30 s. 3. The attempt at a solution I solved for the frictional force acting on the block and got 9.64 N. I need to solve for the coefficient of friction. I am having some trouble figuring that out. Im not sure how to find the normal force and once i get the normal force do I use the formula force(friction) = mu * normal force Any help would be appreciated.