A triangular gate with a base width of 2 m and a height of 1.5 m lies in a vertical plane. The top vertex of the gate is 1.5 m below the surface of a tank which contains oil of specific gravity 0.8. Considering the density of water and acceleration due to gravity to be 1000 $$kg/m^3$$ and 9.81 $$m/s^2$$, respectively, the hydrostatic force (in kN) exerted by the oil on the gate is __________.

Three rigid buckets, shown as in the figures (1), (2) and (3), are of identical heights and base areas. Further, assume that each of these buckets have negligible mass and are full of water. The weights of water in these buckets are denoted as W₁, W₂, and W₃ respectively. Also, let the force of water on the base of the bucket be denoted as F₁, F₂, and F₃ respectively. The option giving an accurate description of the system physics is

A 15 cm length of steel rod with relative density of 7.4 is submerged in a two layer fluid. The bottom layer is mercury and the top layer is water. The height of top surface of the rod above the liquid interface in 'cm' is