ok, our class got an assignment where we have to derive an equation for coefficient of static friction between our text book (inclined at an angle theta) and a coin. The vale of the angle and the mass of the coin are not given. I have come up with the following equation and need to know if it is correct. u = Ff(static)/Fnormal *using components of the force of gravity, i determined Ff to be FgxSINxTheta and Fnormal to be FgxCOSxtheta so, u = FgxSINxTheta/FgxCOSxtheta does this seem correct? thanks for looking.