You are riding in an elevator on the way to 18th Floor in your dormitory. The elevator is accelerating upward with a=1.90m/s². Besides you is the box containing your new computer; box and contents have a total mass of 28.0 kg. While the elevator is accelerating upward, you push horizontally on the box to slide it at constant speed toward the elevator door. If the coefficient of kinetic friction between the box and elevator floor is Mk=0.32. What magnitude of force must you apply?