1. The problem statement, all variables and given/known data A 1.0 kg physics book is on a 20 degree slope. It is connected by a string to a 500 g coffee cup dangling at the bottom side of the incline. The book is given a push up the slope and released with a speed of 3.0 m/s. The coefficients of friction are us = .50 and uk = .20. a. How far does the book slide? b. At the highest point, does the book stick to the slope, or does it slide back down? 2. Relevant equations F=m*a vf^2 = vi^2 + 2as 3. The attempt at a solution So I found four forces: Tension of the rope pulled by the weight, fk (friction force), force of gravity at a 20 degree angle, and normal force. n = mgcosx = (9.8)(1)cos20 N.........fk = uk*n = (.2)n = 1.842 N T = mass of cup * 9.8 = 4.9 N Fg = mgsinx = (1)(9.8)sin20 = 3.35 N ...so I get (Fnet)x = ma = -4.9N - 1.842N - 3.35N = -10.095 ...so... a = (-10.095)/(1) = -10.095 m/s^2 But when I put this value of acceleration into vf^2 = vi^2 + 2as, or 0=9 + 2(-10.095)s, I get .446m. The correct answer is .67m. What did I do wrong? I'm pretty sure it's around the (Fnet)x part. Thanks for any help.