Http://www.nature.com/scitable/topicpage/inheritance-of-traits-by-offspring-follows-predictable-6524... this should answer all questions you have on this specific subject in science
Answer:
Advantages of Hydroelectric Energy
1 Renewable
Hydroelectric energy is renewable. This means that we cannot use up. However, there’s only a limited number of suitable reservoirs where hydroelectric power plants can be built and even less places where such projects are profitable.
2 Green
Generating electricity with hydro energy is not polluting itself. The only pollution occurs during the construction of these massive power plants.
3 Reliable
Hydroelectricity is very reliable energy. There are very little fluctuations in terms of the electric power that is being by the plants, unless a different output is desired. Countries that have large resources of hydropower use hydroelectricity as a base load energy source. As long as there is water in the magazines electricity can be generated.
4 Flexible
As previously mentioned, adjusting water flow and output of electricity is easy. At times where power consumption is low, water flow is reduced and the magazine levels are being conserved for times when the power consumption is high.
5 Safe
Compared to among others fossil fuels and nuclear energy, hydroelectricity is much safer. There is no fuel involved (other than water that is).
Answer: 
Explanation:
Centripetal acceleration 
is calculated by the following equation:
Where:
is the Earth's orbital speed
is the orbital radius
Answer : The mechanical energy of the rock is, 134 J
Solution :
As we know that the mechanical energy is equal to the sum of the kinetic energy and the potential energy.
The formula used for mechanical energy is,
where,
M.E = mechanical energy
K.E = kinetic energy
P.E = potential energy
m = mass of an object = 2 Kg
v = velocity of an object = 6 m/s
h = height = 5 m
g = acceleration due to gravity = 
Now put all the given values in the above formula, we get the mechanical energy of the rock.
![M.E=[\frac{1}{2}(2Kg)\times (6m/s)^2]+(2Kg\times 9.8m/s^2\times 5m)=134\text{ Kg }m^2s^{-2}=134J](https://tex.z-dn.net/?f=M.E%3D%5B%5Cfrac%7B1%7D%7B2%7D%282Kg%29%5Ctimes%20%286m%2Fs%29%5E2%5D%2B%282Kg%5Ctimes%209.8m%2Fs%5E2%5Ctimes%205m%29%3D134%5Ctext%7B%20Kg%20%7Dm%5E2s%5E%7B-2%7D%3D134J)
Therefore, the mechanical energy of the rock is, 134 J
The expression 75 meters per second southeast best describe velocity as it involves magnitude and direction. From the example, the magnitude is 75 m/s (also know as speed) and the direction is southeast. Both are needed to define velocity — usually this happens to moving vehicles or automobiles.
