A tank measuring 3 m (l) x 3 m (b) x 2 m (h) contains water to 80% of its capacity. The tank is moving with a uniform velocity along a smooth horizontal surface.

(i) Will the free surface of water be horizontal? If not, sketch the nature of the free surface.

(ii) From t = 5 s the tank is accelerated along its length at a m/s^{2}. Will the free surface of water be horizontal? If not, sketch the nature of the free surface.

(iii) Determine the maximum value of acceleration a such that water does not spill over the tank.

(iv) Complete the following statement by choosing the correct option.

During accelerated motion of the water tank an air bubble trapped inside will move ________ .

(a) Parallel to the direction of acceleration a.

(b) In a direction opposite to the direction of a.

(c) Vertically upward.

(d) In a direction perpendicular to the free surface of the water.