Alan is using the equation mg sin A = umg cos A to determine the coefficient of friction, u, between a flat rock and a metal ramp. Find u to the nearest hundredth, if the rock begins to slide at 19º.
If you start with mg sin(A) = umg cos(A)
and divide both sides by mg, you get sin(A) = ucos(A)
Divide both sides by cos(A) to get tan(A) = u
If you enter 19° for A: u = tan(19) --> u = 0.34
At least, that's the math; I'm not so sure about the physics.
