: match each description below with the type of star that is described. You may assume that all of the stars described have approximately the same mass as the Sun. This is an adaptation of Thought Question 16, page 847 in OpenStax Astronomy. A. A star with no nuclear reactions going on in the core, which is made primarily of carbon and oxygen B. A star of uniform composition from center to surface; it contains hydrogen but has no nuclear reactions going on in the core. C. A star that is fusing hydrogen to form helium in its core. D. A star that is fusing helium to carbon in the core and hydrogen to helium in a shell around the core.

Explanation:

A. White Dwarf: It is the end stage of a Sun-like star. At the end the red giant star will throw away the outer layers in the form a shell and in the center a hot and bright core will remain. This core consists of carbon and oxygen but the conditions are not suitable to start the fusion of carbon and oxygen.

B. Protostar: It is the initial stage of a star. Here the fuel is available but still the temperature and pressure are not enough to start the nuclear fusion.

C. Main Sequence Star: A star that is fusing Hydrogen in the core to make Helium and releasing the energy in this process. Sun is currently in its main sequence stage. A star spend 90% of its lifetime in main sequence stage.

D. Red Giant Star: In such stars, the hydrogen has been exhausted and only Helium is left. As the core starts contracting under gravity, the conditions are apt for the fusion of Helium to begin. Helium starts fusing to make carbon while in the outer layer Hydrogen to Helium process goes on. As a result the star expands.

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.