Law of conservation of Mass This is a principle used in analysis of chemical reactions .
o A chemical reaction is basically a rearrangement of atoms among different molecules . o If the total binding energy of the reacting molecules is less than the total binding energy of the product molecules , the difference appears as heat and the reaction is exothermic . o The opposite is true for energy absorbing ( endothermic ) reactions . o Since the atoms are merely rearranged but not destroyed , the total mass of the reactants is the same as the total mass of the products in a chemical reaction .
o Mass is related to energy through Einstein theory , E = mc 2 , c – speed of light in vacuum
Law of conservation of linear momentum
Symmetry of laws of nature with respect to translation in space is termed as law of conservation of linear momentum .
Example law of gravitation is same on earth and moon even if the acceleration due to gravity at moon is 1 / 6 th than that at earth . o
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Law of conservation of angular momentum
Isotropy of space ( no intrinsically preferred direction in space ) underlies the law of conservation of angular momentum . o