Answer: C. Binary star systemsLet’s see your options:
a) The <em>color of the star</em>: the color is not used in calculating the mass of a star, because it has no relation to it. Think about a red supergiant and a red dwarf: they have the same color, but they are completely different stars, with respectively a big and a small mass.
b) <em>Kepler’s laws</em>: these laws can be applied in what is called the “approximation of 1 body”, which means that is assumed that one body has a much bigger mass than the other and can be considered at rest. This is the case of a star-planet system and the mass that can be calculated is that of the planet.
c)<em> Binary star systems</em>: these are the only cases in which is possible the direct measure of the mass of the stars. Binary systems are classified as follows:
- Visual binaries: each star can be resolved and the motion around the center of mass can be measured.
- Astrometric binaries: only one star is visible, but the presence of the companion can be inferred by the movement of the first star around the system’s center of mass.
- Eclipse binaries: the two stars are not resolved (separated), but the luminosity varies periodically when one star eclipses the other.
- Spectroscopic binaries: the two stars are not resolved, but their spectrum reveals that they are a binary system.
In all these cases we have a “two-body problem” that can be solved by changing system of reference: the motion of bodies 1 and 2 is equivalent to the motion of a body of mass equal to the system’s reduced mass
moving in the potential generated by the total mass (M1 + M2) considered at rest. Hence, we can determine the masses of the two stars.
Density = Mass divided by Volume
Answer:
unbalanced force
Explanation:
According to Newton the determining factor on if and how an object will move is the unbalanced force acting upon that object. In Newton's first law he states that an object will remain at rest unless acted on by an unbalanced force. This unbalanced force needs to be stronger than any opposite force being acted upon by the same object. Enough so that the object exits its state of rest and begins moving in the direction in which the force is being applied. If the force is not strong enough to overcome the opposite forces then the object will not move.
Thank you for posting your question here at brainly. I hope the answer will help. Below are the choices that can be found elsewhere:
<span>A. 1.5 * 10^3 Watts
B. 7.3 * 10^2 Watts
C. 3.5 * 10^2 Watts
D. 2.5 * 10^2 Watts
</span>
<span>Work = force*displacement = 10^2*87 = 8,700 joule
Power = work/time = 8,700/6 = 1.45*10^3 (rounded up to 1.5 kw). The answer is A. </span>