<h2>The symbol is called an Alpha and means <em><u>"varies as"</u></em></h2>
Mass is the actual amount of material contained in a body and is measured by kg, gm, etc. Whereas weight is the force extorted by the gravity on that object mg. Note that mass is independent of everything but weight is different on earth, moon, etc.
Well, in some systems the atoms melt or burn or change state like from liquid to gases when they reach a certain temperature. This could decrease the energy in the system.
Hope I helped
