I figured out the horizontal friction force, Fpx to be 55.11 N and the normal force exerted vertically to be 190.8 N. And the other info given is F = 84 the lawn mower has a mass of 13 kg and moves at a constant speed. The lawn mower is at an angle of 49 degrees to the horizontal. I need to determine the force the person must exert on the lawn mower to accelerate it from rest to 1.3 m/s in 2.0 seconds (assuming the same retarding force). Do I use the equation 84 cos 49 + F (friciton) = ma??? Or how do I set up this problem?