Final answer:
The absolute pressure on a submarine at a depth three times its original, under the assumption of constant seawater density, would be 30 ATA. This is calculated based on the principle that pressure increases by 1 ATA for roughly every 10 meters of depth in seawater.
Step-by-step explanation:
The subject of this question is clearly Physics since it deals with the principles of pressure and its variation with depth in a fluid, which is a common topic within the study of physics. Specifically, the question pertains to how pressure at different depths in the ocean affects a submarine.
To calculate the absolute pressure acting on the submarine at a new depth which is three times its original depth, one needs to understand that pressure increases with depth in the ocean. For every 33 feet (or approximately 10 meters) of salt water, the pressure increases by 1 atmosphere absolute (ATA).
The submarine initially experiences 10 ATA. Assuming the additional pressure from the water is proportional to depth, tripling the depth would triple the additional pressure from the water. Hence, we would expect an additional 20 ATA from the water, resulting in a total of 30 ATA at the new depth.
Note that real-life applications may require taking into account other factors such as the variations in seawater density, but for the scope of this question and the provided data, 30 ATA is the answer we are looking for.