Conservation of energy?

Jeff Frizzell: A perpetual motion machine would be a machine that continues to do work without continuous addition of energy, which IS a violation of the law of conservation of energy since work, by definition, is the transfer of energy. A spinning object in the absence of any resistive forces or interference will continue to spin because there is no mechanism by which energy is transferred or dissipated. No work is being done, so the quantity of kinetic energy remains constant, and it continues to spin at the same angular speed....Show more

Aubrey Tirri: it won't keep spinning in space forever. tidal forces will eventually slow it down (see, the moon).

Hope Lundmark: Calm down.'Conservation of energy` means that energy is not created or destroyed.If there's no friction, where would the energy go?Nowhere, so the mass keeps spinning.That's a pretty special case.Now suppose that we put that mass in orbit around a larger one.As it spins the gravity of the larger! mass 'stretches' it in a moving pattern.Its core heats up, and some energy is lost as heat. The spin slows.(We actually see this in the moons of Jupiter, and it's the reason that one side of our own Moon always faces Earth.) 'Perpetual motion' is considered impossible because friction losses are considered unavoidable. 'Conservation of Mass' is essentially the same thing. If you look hard enough, you can always find out where all the mass went.As you go further with your studies you will learn that mass can be transformed into energy, and vice versa, according to a fixed ratio, (E = MC^2, - basically a little mass = one hellofoa lot of energy),and the laws are combined and re-written into a single law of 'Conservation of Mass/Energy' but that's just something to look forward to....Show more

Rayford Speziale: I used to believe that energy doesn't get destroyed, but the reality is that it does get destroyed. The world needs to move away from the first law of thermodyna! mics, which states that energy doesn't get destroyed, to the s! econd law of thermodynamics, where energy DOES get destroyed.