1. The problem statement, all variables and given/known data A block with initial velocity of 10 m/s is sent up an incline at 30 degrees from the horizontal. The coefficient of friction is 0.2x where x is the displacement. Find the maximum distance the block moves up the incline. 2. Relevant equations F = ma (1/2)mv^2 mgh 3. The attempt at a solution I decided to try and use energy for this one. Initial energy is (1/2)m(10)^2 + friction and final is mgh because the block comes to rest eventually. So: (1/2)m(10)^2 + friction = mgh Friction = coefficient * Normal force, so Friction = 0.2x * mgcos(30). Therefore: (1/2)m(10)^2 + (0.2x*mgcos(30)) = mgh Masses cancel out: 50 + (0.2x*gcos(30)) = gh We want to find x because x is along the incline, and sin(30) = h / x, so h = xsin(30) and substitute back in: 50 + (0.2x*gcos(30)) = g(xsin30) Simplify: 50 + 1.697x = 4.9x 50 = 3.203x x = 15.6 meters The solution is 5.31 meters, though. What have I done incorrectly?