A box 'A' is lying on the horizontal floor the compartment of a train running along horizontal ralls from left to right. At time 't', it decelerates. Then the resultant contact force R by the floor on the box is given best by :

A closed cubical box is completely filled with water and is accelerated horizontally towards right with an acceleration a. The resultant normal force by the water on the top of the box.

A closed cubical box is completely filled with water and is accelerated horizontally towards right with an acceleration a. The resultant normal force by the water on the top of the box.

A closed cubical box is completely filled with water and is accelerated horizontally towards right with an acceleration a. The resultant normal force by the water on the top of the box.

A boy of mass M is applying a horizontal force to slide a box of mass M' on a rough horizontal force to slide coefficient of friction between the shoes of the boy and the floor is mu and that between the box and the floor is mu' . In which of the following cases it is certainly not possible to slide the box?