A vessel with square cross-section and height of \( 6 \, \text{m} \) is vertically partitioned. A small window of \( 100 \, \text{cm}^2 \) with hinged door is fitted at a depth of \( 3 \, \text{m} \) in the partition wall. One part of the vessel is filled completely with water and the other side is filled with the liquid having density \( 1.5 \times 10^3 \, \text{kg} / \text{m}^3 \). What force one needs to apply on the hinged door so that it does not get opened?
(Acceleration due to gravity \( = 10 \, \text{m} / \text{s}^2 \))
