1. The problem statement, all variables and given/known data The dimension h is to be determined to that a worker can comfortably slides boxes weighing up to 106 lb up and down a frictionless incline. If the worker can apply a 50 lb horizontal force to the box, what is the largest value h should have? Hint given: Before taking any other action, draw a FBD of the box. Isolating the box from its surroundings requires a closed surface passing between the worker's hands and the box as well as between the bottom of the box and the incline. It may be more natural to define and solve for an angle of inclination α and then determine h from tanα = h/6. Picture and force body diagram attached http://imgur.com/a/EBBCi 2. Relevant equations ΣFx=0 ΣFy=0 tanα = h/6 3. The attempt at a solution I am having a hard time differentiating between the force of 50lb along the ramp, and then the distance 6ft since they are not the same type of thing. Do I need to find the distance of the 50lb force? Or the force of 6ft? Because from there I could solve for α. I am not sure if I am calculating a system that's in equilibrium since he is actively pushing the box up.