A classmate says that all this stuff about no perpetual motion is bunk; that atoms, planets, stars, and everything are in perpetual motion. What distinction is being missed here?
Solution 47E He missed the distinction between the perpetual motion and perpetual motion machine. The two things are different. A body is in perpetual motion means the body will continue its motion indefinitely. This does not violates any law and hence it is very much possible. That’s why we can see that stars, planets, molecules atoms all those things are in motion forever. But perpetual motion machine is different. A perpetual motion machine is a device that can generate more energy that it consume, in other words it can continue generating energy without supplying any thing for ever. This violates the first law of thermodynamics or the conservation of energy. Hence it is not possible.