Final answer:
The subject of this question is Physics. It is about the thermal expansion of a water tank and its ability to withstand tension caused by volume expansion.
Step-by-step explanation:
The subject of this question is Physics. The question is asking about the thermal expansion of a water tank and its material's ability to withstand tension caused by volume expansion.
Thermal expansion is the increase in size or volume of a substance when its temperature changes. In this case, as the water in the tank is heated, it will expand, causing the volume of the tank to increase. The tank material is designed to tolerate a 2% increase in volume due to the expansion of the water.