Creating Energy! I have this doubt in my mind for a long time, see if we rotate a fan in space: it would keep on rotating forever and would never stop. Due to no air friction present in space. I could never really accept this fact. So i thought of the following situation: I take a fan and rotate it, and this fan is on the top of a turbine. So wouldn't the turbine generate electricity forever? Or if you cant except a turbine, lets say i attach and axle to the fan which in turn has magnets attached to it, There are other magnets surrounding it and remember the thing is rotating, so it would make energy...? or if i make a ball go around an axle. I hope i have made myself clear, that according to me the ball/fan would not stop due to absence of friction. Would it? Why?
Sorry if this sounds stupid. I am just a 15 year old young student, enthusiastic about physics so i have a habit of challenging all the theories before accepting them... 
Update
From the question i mean to say that will this cause the law of conservation of energy to fail?(ofcourse it won't and i know it) but I want someone who could prove it to me without saying that ....as energy is conserved.... Got it, what i am trying to ask?
 A: The problem with that type of schemes is that, because of Newton's third law of motion, when the fan applies a force to some external system to perform work on it, the external system also applies a force on the fan in a direction that will tend to stop it. This performs exactly the same amount of work against the fan's initial energy as it is performing on the system, because the forces are equal and opposite, and the distance travelled is the same. The net result is that the kinetic energy of the fan does eventually wind down to zero, if it is connected to an external system like that.
A: Lenz's rule is related to the principle of conservation of energy. It states that:
The induced current produced in a circuit always flows in such a direction that it opposes the change or the cause that produces it.  
So, induced current is going to stop the fan in your case.   
I hope the fan is connected to the coil which rotates in between the magnets. As the induced current opposes the magnetic flux, there is a need to do work. Every time you do work, current will be produced by the expense of mechanical work done.
