how ecutaly we can convert energy by dropping the water down hill?

Answer 1

By the conservation of energy law, all mass, including water, has a total energy TE = PE + KE = mgh + 1/2 mv^2. When that water is still in the pool at the top of the hill, the water's velocity v = 0; so KE = 1/2 mv^2 = 0. That means, and this is important, all the energy in that pool of water at the top of the hill is potential energy (PE), PE = mgh; where m is the mass of the water, g = 9.81 m/sec^2 on Earth's surface, and h is the height of your hill.

Now the water plunges over the rim of the pool and down the hill as a waterfall. What's happening to PE? As PE = mgh, it is clear that PE --> 0 as the height of the water above the foot of the waterfall also approaches 0 (i.e., h --> 0). Hey, are we destroying energy here? Isn't that contrary to the conservation of energy law?

Nope, not at all. Remember, at the top of the hill KE = 0 because the water is still (v = 0). But as the water falls, which is why we call it a waterfall, the velocity increases because of the work done on it by gravity. In other words, as PE --> 0, KE --> > 0, kinetic energy gets bigger. That is, we're not destorying PE, but we are converting it into KE.

And the work done on the water while it falls down the hill converts PE into KE. In fact, lacking any other work (like friction force), when the water reaches the bottom of the cascade, all the PE will be converted into KE.

So we can write TE(h) = PE = KE = TE(0); that is the total energy at the top of the hill, at h, equals the total energy at the bottom of the hill, at h = 0. The difference is in what that total energy is made of.

OK, then, at the bottom of the hill (or close to the bottom), most of that total energy in the water is KE. Can we do anything useful with that? Sure, as one answer suggested, put a waterwheel under that falling water with KE and cause the kinetic energy to turn that wheel and grind the corn in a mill.

Or, maybe more timely, turn that wheel and generate electricity, another form of energy. But, and this is a big BUT, because of the work to move the wheel, and overcome friction and other such things, not all of the KE will become EE, electrical energy. And that's called inefficiency because some of that energy in KE is converted to energy that is not useful, and we call that entropy.

Answer 2

WTH is ecutaly??

Energy conversion from potential energy to Electricity I think was about 30-40% at best using a turbine-wheel setup.

Answer 3

normally the water will turn a ''wheel'' that is hooked up to a generator and some batteries that will harnes and make the power that alot of people use everyday....this is the point of a waterdamm

Answer 4

what you are referring to is hydroelectric power and if you have seen hoover dam or any other dams they are making power from water current.