a. A dam is usually built at the site of hydroelectric power. As water accumulates, its potential power for producing electric power increases. As this water moves downstream from the dam, mostly through a fall, its kinetic energy is harnessed by turbines and converted to electric energy.
b. One factor is the height of the fall of the water from the dam. The higher the height the higher the kinetic energy of the water and hence can be converted to higher electric energy. The higher the number of coils of the turbine generator being rotated by the water, the higher the conversion to electric current.
c. One is impoundment. This type is the most common and involves the building of a dam to store water and later the water is released to turn turbines. The second type is diversion. This type does not require a dam. Some water is diverted from the main river to create a pen-stock that runs a turbine.
d. The advantage of hydroelectric power is that is is a clean energy source hence does not cause global warming. Global warming can have economic consequences. The operating cost of this type of plant is low hence the costs of electricity are able to be kept low for the consumers. 2 disadvantage is that creating a dam upstream causes a change in the physical and chemical characteristics of the river or water bodies affecting ecosystems. Another is that electricity is dependent on the water regime hence dependency is tied to climate.
Answer:
It is dangerous when there are flammable gases or a high concentration of oxygen. A spark could ignite the gases and cause an explosion. It is dangerous when you touch something with a large electric charge on it. The charge will flow through your body causing an electric shock.
Answer:
it appears to be farther away than it actually is, and therefore smaller then the object itself.
Answer: H
Explanation:
When beavers dam a stream they slow the movement of water. Behind the beaver dam, a pond of still water is formed. This pond is then colonized by animals and plants that typically live in lakes rather than streams.
Let the distance between the towns be d and the speed of the air be s.
distance = speed * time
convert the minutes time into hours.
When flying into the wind, ground speed will be air speed MINUS wind speed, hence the against the wind trip is described by:
d
s−15
=
7
3
return trip is then :
d
s+15
=
7
5
Cross-multiplying both we get the two-variable system:
3d=7∗(s−15)5d=7∗(s+15)
3d=7s−1055d=7s+105
subtract first equation from second equation we get
2d=210d=105km
Substitute the value of d in the above equations for s.
5∗105=7s+1057s=420s=60km/hr
