I've already made my own attempt at this problem, which was marked incorrect. I'm having trouble determining the correct approach. 1. The problem statement, all variables and given/known data G: m=50 kg, W= 2.2E3 J, (delta)d=60 m, speed is constant, coefficient kinetic friction = 0.26 R: Force applied, and angle 2. Relevant equations These are the equations I have: W = F(delta)d cos(theta) 3. The attempt at a solution The velocity is constant, so net force must be 0. Therefore, I thought that applied force must be equal to force of friction, or (mu)Fn. This doesn't account for the angle, and is incorrect. Can anyone offer help? I get the feeling I'm only missing some basic equation. Thanks!