Answer: 
Explanation:
We can solve this with the Law of Universal Gravitation and knowing the acceleration due gravity 
of an object above the surface of the planet decreases with the distance (height) of this object from the center of the planet.
Well, according to the law of universal gravitation:
(1)
Where:
is the module of the force exerted between both bodies
is the gravitational constant
is the mass of the Earth
are the mass of each communications satellite
is the distance between the center of the Earth and the satellite
is the radius of the Earth
is the height of the satellite, measured from the Earth's surface
On the other hand, we know according to <u>Newton's 2nd law of motion:</u>
(2)
Combining (1) and (2):
(3)
Isolating :
(4)
Remembering :
(5)
Finally:
Answer:
The electron is a subatomic particle, symbol e⁻ or β⁻ , whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure
Explanation:
functions of electrons
and electrons being the negatively charged particles of atom. Together, all of the electrons of an atom create a negative charge that balances the positive charge of the protons in the atomic nucleus
Answer:
η = 40 %
Explanation:
Given that
Qa ,Heat addition= 1000 J
Qr,Heat rejection= 600 J
Work done ,W= 400 J
We know that ,efficiency of a engine given as
Now by putting the values in the above equation ,then we get
η = 0.4
The efficiency in percentage is given as
η = 0.4 x 100 %
η = 40 %
Therefore the answer will be 40%.
The refrigerator's coefficient of performance is 6.
The heat extracted from the cold reservoir Q cold (i.e., inside a refrigerator) divided by the work W required to remove the heat is known as the coefficient of performance, or COP, of a refrigerator (i.e., the work done by the compressor). The required inside temperature and the outside temperature have a significant impact on the COP.
As the inside temperature of the refrigerator decreases, its coefficient of performance decreases. The coefficient of performance (COP) of refrigeration is always more than 1.
The heat produced in the cold compartment, H = 780.0 J
Work done in ideal refrigerator, W = 130.0 J
Refrigerator's coefficient of performance = H/W
= 780/130
= 6
Therefore, the refrigerator's coefficient of performance is 6.
Energy conservation requires the exhaust heat to be = 780 + 130
= 910 J
Learn more about coefficient here:
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Answer: O horizon
Horizons refers to the distinct layers of soil lying parallel to the earth surface. Horizons develop as a result of soil formation. Soil forms as a result of weathering or rocks and addition of organic matter from the decomposition of plant and animal waste. Each horizon differs from the others on the basis of color, texture, type of particles present in the soil, type of minerals present and amount of organic matter present in the soil.
O horizon is the soil horizon that is located closest to the earth's crust. This horizon consist of undecayed or partially decayed animal and plant waste like shedded leaves, bark, animal skin and feces. As, the matter remains undecomposed, therefore, this horizon consists of low amount of organic matter and it is less fertile for plant growth.
