1. The problem statement, all variables and given/known data Two men loading a 900 kg piano onto a truck lose control and the piano slips, rolling down the loading ramp. The ramp is a 12 degree incline that is 3.2m long. If the piano accelerates down the ramp at 0.4m/s^2, find the coefficient of rolling friction. 2. Relevant equations F=ma 3. The attempt at a solution a=g(cos)(theta)-(mu)g(sin)(theta mu=g(cos)(theta)=9.8(cos12)+0.4 mu=9.9 This looks wrong. Where did I mess up? Thanks!