Hydrostatic pressure increases with depth

Steps:

• Hydrostatic pressure formula: P = ρgh + P_atm, where h is depth from surface.
• For a submerged block, pressure on side faces rises linearly from top to bottom.
• Force on equal areas equals pressure times area, so arrows represent forces scaling with depth.
• Correct diagram shows shortest arrows at top, longest at bottom.

Why A is correct:

• Depicts forces increasing downward, matching P ∝ h from hydrostatic principle.

Why the others are wrong:

• B: Shows uniform forces, ignoring depth-dependent pressure.
• C: Shows forces decreasing with depth, reversing hydrostatic gradient.
• D: Shows nonlinear or equal forces, violating linear pressure increase.

Final answer: A