1. The problem statement, all variables and given/known data A jet-powered flatbed truck has a crate of mass m, which is strapped down to the truck with a tension three times the weight of the box. Find the maximum acceleration without having the box slide. Us= .9, Uk=.7 2. Relevant equations Fun= SUM Fun= ma Ff= -(Us) Fn 3. The attempt at a solution I've figured out the Y components, and resulted in the Ff= 35.3m, my only problem now is where to go from here. I can't for the life of me figure out the other horizontal force other than Ff. when I attempt the solution, I get Fun=SUM = Ff =35.3m Fun=ma 35.3m=ma 35.3=a I know the answer is -7.7 but I can't seem to think of the opposing horizontal force.