Most hydroelectric power plants have a dam and a reservoir. These structures may obstruct fish migration and affect their populations. Operating a hydroelectric power plant may also change the water temperature and the river's flow. These changes may harm native plants and animals in the river and on land. Reservoirs may cover people's homes, important natural areas, agricultural land, and archaeological sites. So building dams can require relocating people. Methane, a strong greenhouse gas, may also form in some reservoirs and be emitted to the atmosphere. Reservoir construction is "drying up" in the United States Gosh, hydroelectric power sounds great -- so why don't we use it to produce all of our power? Mainly because you need lots of water and a lot of land where you can build a dam and reservoir, which all takes a LOT of money, time, and construction. In fact, most of the good spots to locate hydro plants have already been taken. In the early part of the century hydroelectric plants supplied a bit less than one-half of the nation's power, but the number is down to about 10 percent today. The trend for the future will probably be to build small-scale hydro plants that can generate electricity for a single community. As this chart shows, the construction of surface reservoirs has slowed considerably in recent years. In the middle of the 20th Century, when urbanization was occurring at a rapid rate, many reservoirs were constructed to serve peoples' rising demand for water and power. Since Hydroelectric energy is produced by the force of falling water. The capacity to produce this energy is dependent on both the available flow and the height from which it falls. Building up behind a high dam, water accumulates potential energy. This is transformed into mechanical energy when the water rushes down the sluice and strikes the rotary blades of turbine. The turbine's rotation spins electromagnets which generate current in stationary coils of wire. Finally, the current is put through a transformer where the voltage is increased for long distance transmission over power lines.
Hydroelectric-power production in the United States and the world!
(sorry this is the second part)
Answer:
This is a rather complicated thing to explain so I'll try my best. To put it in simple term the sun has whats called a SOI (sphere of infleunce) and anything inside of this is effected by the gravity of that planet or sun in this case. The earth is inside of this sphere of influence. The earth has a constant velocity that is making it move away from the sun but since it's in the suns SOI the path in which the earth moves is changed in a way that causes it to spin around the sun. The same thing is happening with the moon. I'm not 100% sure on this but I think the reason the moon does not just fly away towards the sun is because it is closer to earth and is more effected by earths SOI. Hope this cleared things up for you.
All of the answers would be correct,
hope this helped!! <span />
