1. The problem statement, all variables and given/known data A physics student is performing an experiment to determine the coefficient of friction between a physics textbook and a 2.5 m wooden ramp. He places the textbook, which has a mass of 1.2 kg, on the inclined ramp and gradually increases the angle of the incline. At an angle of 30 degrees, the textbook starts to slip. It slides down the ramp in 4.0 s. Determine the coefficient of friction. 2. Relevant equations 3. The attempt at a solution Well i was working on it with my friend in class, and he came up with friction = tan 30 degrees = 0.58 but then, I dont think thats all to it right? Any help please?