Which best describes stellar equilibrium?

Stellar equilibrium is also known by its other term hydrostatic equilibrium. A star is considered to be in equilibrium when the pressures located in the star balance out the force of gravity. The pressure is thermal pressure that results from the mixture reactions that is happening in the star's core.

A star will remain in equilibrium until such time when the supply of hydrogen in the core is exhausted. After that the star will start to collapse and heat up until another fusion reactions begin.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )