Answer:
The atomic number 26(iron) is the threshold value below which the fusion might occur.
Explanation:
Nuclear fusion is a reaction in which two or more nuclei are combined to form one or more different atomic nuclei and subatomic particles.
Energy released in a fusion reaction is because of a key feature of nuclear matter called the binding energy which is a measure of the efficiency with which its constituent nucleons are bound together.
As we go up in atomic number, the energy released per nuclei goes down until it hits a minimum which is for atomic number 26 (iron) and fusion is not possible.
The correct answer is option #4. The greatest obstacle to developing solar energy is large areas required to collect sufficient energy. Solar energy is the energy that is the sun is producing and being converted into thermal energy that can be used for everyone's daily lives.
This is true due to the reaction that happens from water evaporating and leaving the sugar crystals behind to form.
<h2>
Answer: 7020.117 m/s</h2>
Explanation:
The velocity of a satellite describing a circular orbit is<u> constant</u> and defined by the following expression:
(1)
Where:
is the gravity constant
the mass of the massive body around which the satellite is orbiting, in this case, the Earth
.
the radius of the orbit (measured from the center of the planet to the satellite).
This means the radius of the orbit is equal to <u>the sum</u> of the average radius of the Earth 
and the altitude of the satellite above the Earth's surface 
.
Note this orbital speed, as well as orbital period, does not depend on the mass of the satellite. It depends on the mass of the massive body (the Earth).
Now, rewriting equation (1) with the known values:
