Question

Each of the beakers shown is filled to the same depth h with liquid of density ρ. The area A of the flat bottom is the same for each beaker. Which of the following ranks the beakers according to the net downward force exerted by the liquid on the flat bottom, from greatest to least force? 

(A) I, III, II, IV 

(B) I, IV, III, II 

(C) II, III, IV, I 

(D) IV, III, I, II 

(E) None of the above, the force on each is the same.

Answer 1

Correct option (E) None of the above, the force on each is the same.

Since the pressure in a fluid is only dependent on the depth, they all have the same fluid pressure at the base. Since all of the bases have the same area and the same liquid pressure there, the force of the liquid given by P = F/A would be the same for all containers. Note: IF instead this question asked for the pressure of the container on the floor below it, the container with more total mass in it would create a greater pressure, but that is not the case here.