Answer:

Explanation:
We are given that
Gravitational force=
r=0,U(0)=0
We know that
Gravitational potential energy=


Substitute r=0 ,U(0)=0


Substitute the value

Answer:
<em>The comoving distance and the proper distance scale</em>
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Explanation:
The comoving distance scale removes the effects of the expansion of the universe, which leaves us with a distance that does not change in time due to the expansion of space (since space is constantly expanding). The comoving distance and proper distance are defined to be equal at the present time; therefore, the ratio of proper distance to comoving distance now is 1. The scale factor is sometimes not equal to 1. The distance between masses in the universe may change due to other, local factors like the motion of a galaxy within a cluster. Finally, we note that the expansion of the Universe results in the proper distance changing, but the comoving distance is unchanged by an expanding universe.
The heat and energy of coal burning is more easier and more efficient to turn into electricity than any method using renewable resources.
Answer:
The pressure exerted by the girl is 245,000 N/m²
Explanation:
Given;
mass of the girl, m = 50 kg
area of the girl's shoe, A = 0.002 m²
The pressure exerted by the girl is calculated as follows;

Therefore, the pressure exerted by the girl is 245,000 N/m²
The answer is A.
Hydroelectric, which is usually generating electricity through use of a dam.
Solar, energy from the Sun.
Biomass, organic material formed from plant matter.