Am I approach this question right?......finding acceleration 1. The problem statement, all variables and given/known data A tractor applies a force of 1.3kN to the sled, which has a mass of 1.1x10^4 kg. At that point, the co-efficient of kinetic friction between the sled and the ground has increased to .8. What is the acceleration of the sled? 2. Relevant equations 3. The attempt at a solution Given M = 11,000kg Applied Force = 1300 N , let if be Fa Kinetic Friction co-efficient = 0.8 , let it be uK Legend let Fa = applied force let Ff = force of friction m = mass a = acceleration Finding force of friction Ff = uk*Fn = (0.8)* (11000 kg x 9.81m/s^2) = 86 328 N Calculating Acceleration F=ma Fa + Ff = ma a = ( Fa + Ff ) / m = ( 1300 N + 86 328 N) / 11 000 kg = 7.9 m/s^2 I tried to do this question literally 10 times now. I keep getting this answer, but know it's wrong. Maybe my approach isn't correct, or I am missing a negative sign somewhere. Please help.