1. The problem statement, all variables and given/known data The coefficient of friction is to be found from a skateboard and rider rolling down a ramp, which has an angle of 5 degrees. The skateboard accelerates at .5308 m/s^2. The mass of the rider and skateboard is 91.3 kg, or 895 newtons. The other data would be gravity. 2. Relevant equations Coefficient of friction = Fx/Fn 3. The attempt at a solution I found what I thought to be the acceleration the skateboard would have had if it was friction less. That was .8526, however now I am pretty sure I did something wrong. Then I found the force of gravity at 5 degrees, which was 9.39722. But I know there is something very wrong with what I'm doing. Then putting .5308/9.39722 to find a coefficient of about .05. I'm certain I'm doing something wrong, and the mass can be used to find it. But I am lost. Any help would be greatly appreciated!