The world needs a new source of energy, an unspillable source.

Why do we have conservation of energy?

Why do we have conservation of energy?
From vector calculus we can determine when a field is conservative or not. So do we have energy conservation because all physical force fields can be shown to be conservative through vector calculus?

What about the the non conservative electric field created when two opposite sides of two magnets move towards or away from each other creating magnetic flux over time? (Faraday’s Law)