Final answer:
The total water pressure at a depth of 1 km is approximately 10,157,575 Pa or N/m². This calculation includes the pressure exerted by the water column and the atmospheric pressure at sea level.
Step-by-step explanation:
To calculate the water pressure at a depth of 1 kilometer under water, we need to consider both the pressure due to the water column above and the atmospheric pressure at the surface. The formula for fluid pressure due to a column of liquid is given by P = ρgh, where P is the pressure, ρ is the density of the fluid, g is the acceleration due to gravity, and h is the height or depth of the fluid column. Assuming a constant seawater density of ≈ 1025 kg/m³ and standard gravity of 9.81 m/s², the pressure from the water column would be P_water = 1025 kg/m³ * 9.81 m/s² * 1000 m = 10,056,250 Pa or N/m². However, we also have to add atmospheric pressure at sea level, which is approximately 101,325 Pa. Hence, the total pressure at 1 km under water is ≈ 10,157,575 Pa or N/m².