Clean definition of world's most powerful waterfall
Powerful has a very clean definition: Power = Work/time. Work = Force * Distance. The distance is the height of the falls. The Force = Mass * Acceleration. Acceleration is gravity. Mass = Density * Volume. Re-arrange the terms and you get that Power = gravity * height * density * (Volume/time). And there you have it. Average that over the year and you have the unambiguous most powerful falls.