Final answer:
This question deals with the concept of thermal expansion, where the first relieving element establishes the degree of dimensional change in material caused by a change in temperature, calculated using the original area, change in temperature, and coefficient of linear expansion.
Step-by-step explanation:
The question seems to be referring to the concept of thermal expansion in physics, particularly relating to the expansion of materials when they are heated. The first relieving element likely refers to the material's initial response to a change in temperature (AT), where AA is the change in area A, and a is the coefficient of linear expansion. The coefficient of linear expansion varies slightly with temperature, and it is a measure of how much a material expands per degree change in temperature.
When the first relieving element arrives from the change in area (AA), it establishes the degree to which the material has undergone dimensional changes due to thermal expansion. This is calculated by taking the original area of the material, multiplying it by the change in temperature (AT), and then by the coefficient of linear expansion (a).