1. The problem statement, all variables and given/known data A truck is loaded with a large box, which is a uniform rectangular solid 1.8 m tall, 1.0 m wide, and 1.2 m deep. The box sits upright on a truck with its 1.0 m dimension in the direction of travel, and the bed of the truck is sufficiently rough that the load cannot slide. How rapidly can the truck accelerate without tipping the box over? [Hint: Suppose the box is just starting to tip; where is the normal force acting?] 2. Relevant equations This is from the torque/equilibruim section of the physics textbook. 3. The attempt at a solution I set up a free body diagram, made three equations for the forces in the x direction, y direction, and the net torque. But mastering physics says my answer is wrong. How should I set up this problem?