1. The problem statement, all variables and given/known data A 7 kg block on a flat surface moves from 2 m/s to 4 m/s over 5 m. The coefficient of friction between the block and the surface is 1. How much force was used to move the block? 2. Relevant equations Honestly, my physics instructor gave us so many worksheets with so many worksheets, I have no clue which one to use. 3. The attempt at a solution vf^2 = vi^2 + 2a(change in x) 4^2 = 2^2 + 2a(5) a=1.2 F=ma F = 7*1.2 F=8.4 I don't know how friction comes into play though.... Thank you!