Further to that, more confusion. I have always been mystified by these laws of inertia. or acceleration. acceleration= change in velocity or direction. to accelerate a body is to apply a force yes, and if that is the a change in velocity, then this force does work. energy is expended.. (curious can it be expended? not created nor destroyed,) anyway, to continue.. but if this force causes a change of direction, ie cause a satellite to rotate around the earth, (centrepetal force) no work is done , no energy is expended, .. ditto a bearingless flywheel in a vacuum..it will spin forever at constant velocity and claimed to be accelerating. . So the mystery is why are these two actions, (a) a change in velocity representing work done, and (b) a change in direction does not mean work necessarily done.. why are thes actions considered as the same and called acceleration? Thats what makes me rebel against MS. They ignore all the too hard philosophical questions, and charge on regardless. They tested the first bomb, knowing the inherent theoretical danger of a chain reaction. They claim the law of the conservation of Energy, which cannot be created or destroyed, and evolution which claims to come from nothing to eventually reach a higher evolved state, and entropy (is a measure of the unavailability of a system's energy to do work) which says all activity will cease and come to a stop.. a series of obvious contradictions is all I see here. Phil. fromwiki, Notice that detestable manouvre of increasing negativity where I underlined it, as though it were a positive thing ... . We have previously mentioned that a finite universe may be considered an isolated system. As such, it may be subject to the Second Law of Thermodynamics, so that its total entropy is constantly increasing. It has been speculated that the universe is fated to a heat death in which all the energy ends up as a homogeneous distribution of thermal energy, so that no more work can be extracted from any source. (is that evolution or devolution?) Entropy change has often been defined as a change to a more disordered state at a molecular level. or, Entropy - energy broken down in irretrievable heat. or a.. Boltzmann's constant times the logarithm of a multiplicity; where the multiplicity of a macrostate is the number of microstates that correspond to the macrostate. a.. the number of ways of arranging things in a system (times the Boltzmann's constant). a.. a non-conserved thermodynamic state function, measured in terms of the number of microstates a system can assume, which corresponds to a degradation in usable energy. a.. a direct measure of the randomness of a system. a.. a measure of energy dispersal at a specific temperature. a.. a measure of the partial loss of the ability of a system to perform work due to the effects of irreversibility. a.. an index of the tendency of a system towards spontaneous change. a.. a measure of the unavailability of a system's energy to do work; also a measure of disorder; the higher the entropy the greater the disorder. a.. a parameter representing the state of disorder of a system at the atomic, ionic, or molecular level. a.. a measure of disorder in the universe or of the availability of the energy in a system to do work.