<s>[INST] A cylindrical tank with an inner radius of 7m and a filling height of 2.5m is half-filled with water, and a cuboid block of length 2m, width 2m, and height 0.5m is partly submerged in the water. Given the density of water is 1000kg/m^3, what is the approximate buoyancy force (in Newtons) exerted on the block?[/INST]