The Coefficient Of Static Friction Between The Floor And Box

A box 400 kg is on the floor.
The coefficient of static friction between the floor and box. A what is the normal force on the box due to the surface of the shelf. A what is the coefiecent of static friction between the box and the floor. A horizontal force of 50n is applied to the box. A 5kg box is at rest on the floor.
As per the question its given that the acceleration of the box lying on the floor is due to the static friction between box and the train s floor as the box lying is always in stationary condition. The coefficient of static friction between the box and the floor is 0 4. The coefficient of static friction 0 8 between the box and the surface of the shelf. Assume g 10 m s 2.
The maximum acceleration of the 1 47 ms. What is the coefficient of kinetic friction i believe the forces is t of static is 59 and the coefficient of kinetic is 37 let me know if i m right if not please explain.