1. The problem statement, all variables and given/known data A 15.0 kg block is dragged over a rough, horizontal surface by a 74.9 N force acting at 17.6 degrees above the horizontal. The block is displaced 4.91 m, and the coefficient of kinetic friction is 0.266. Find the work done by the 74.9 N force = 351 J Find the work done by the normal force = 0 J What work does the gravitational force do on the block? = 0 J This is the part i can't figure out: How much energy is lost due to friction? And related to that: Find the total change in the block's kinetic energy. 2. Relevant equations Ff = ((mu)k)(mg) E = F*d 3. The attempt at a solution Ef = ((mu)k)(mg) (d) = 0.266*15*9.8*4.91 = 192 J What am I doing wrong?