1. The problem statement, all variables and given/known data A block of mass 4.2 kg which has an initial velocity of 3.3 m/s at time t=0, slides on a horizontal surface. If a constant friction force of 10.2N is exerted on the block by the surface, what is the acceleration? 2. Relevant equations Work Energy Theorum? .5 m vo2 - .5 m v22 v = vo + at 3. The attempt at a solution I found the kinetic energy of the block, then subtracted the 10.2N of friction. Then I solved for the second velocity. I plugged this into the acceleration equasion, but the answer was not correct? Can anyone help me?