سوال ۲۴ کنکور ارشد مهندسی مکانیک ۱۴۰۲

PART C: Reading Comprehension

PASSAGE 3:

One of the major themes that runs through physical science is the Conservation Laws. These laws tell us that an isolated system in equilibrium will have identifiable properties that cannot change. These are often referred to as constants. These constants of an object/system are said to be conserved; and the resulting conservation laws can be considered the most fundamental principle of the system. In mechanics, examples of conserved quantities include energy and momentum. Studying motion from the basis of the law of conservation provides a unique advantage when compared to other methods, the ability to relate that motion to energy. The connection between motion and the conservation laws is possible because all mechanical motion is the result of some form of energy transformation. An understanding that energy is a conserved quantity allows one to follow that energy in all its various forms. Thus, a key question is to ask when studying a particular phenomenon is: Where does the energy of a system come from and where does it go.

The word “key” in line 11 can be substituted by ----------.