All categories

2 years ago

What property of stars can be measured only by using binary-star systems?

Physics

1 answer:

drek231 [11]2 years ago

3 0

Answer:

mass

Explanation:

To expect an understanding of the nature and evolution of the stars, astronomers had to try to determine an important parameter: its mass. This is difficult to determine because neither the luminosity measurements nor the spectral analysis are of any help. The only solution is to resort to astrometry, the precise measurement of stellar positions, and apply it to what is called binary systems, that is, pairs of stars linked by their mutual gravitational attraction and in orbit around each other.

In the solar system there is a law, called the third law of Kepler, that connects the size and period of each planetary orbit and that makes the Sun's mass intervene. This law can be generalized in all bodies in orbit, in particular the members of a binary system. Instead of the mass of the Sun, it is the total mass of the couple that counts. Thus, if it was possible to measure the period and size of a binary system by observation, it would be enough to apply this law in order to calculate the total mass of the pair.

To determine the mass of each star, not just that of the couple, the astronomer had to study in more detail the relative movement of the two members. This allowed him to determine the proportion of each star in the total of the couple and finally obtain the mass of each body.

You might be interested in

A sealed container holding 0.0255 L of an ideal gas at 0.981 atm and 65 ∘ C is placed into a refrigerator and cooled to 41 ∘ C w

user100 [1]

Answer:

0.911 atm

Explanation:

In this problem, there is no change in volume of the gas, since the container is sealed.

Therefore, we can apply Gay-Lussac's law, which states that:

"For a fixed mass of an ideal gas kept at constant volume, the pressure of the gas is proportional to its absolute temperature"

Mathematically:

$p\propto T$

where

p is the gas pressure

T is the absolute temperature

For a gas undergoing a transformation, the law can be rewritten as:

$\frac{p_1}{T_1}=\frac{p_2}{T_2}$

where in this problem:

$p_1=0.981 atm$ is the initial pressure of the gas

$T_1=65^{\circ}+273=338 K$ is the initial absolute temperature of the gas

$T_2=41^{\circ}+273=314 K$ is the final temperature of the gas

Solving for p2, we find the final pressure of the gas:

$p_2=\frac{p_1 T_2}{T_1}=\frac{(0.981)(314)}{338}=0.911 atm$

3 0

2 years ago

9. If everything in the universe – including atoms and particles stop moving, does time stop? Or does time continue even if ever

Vedmedyk [2.9K]

Time stops everything is made out of atoms so if atoms freeze everything freezes

5 0

2 years ago

At t = 0 the components of a radio-controlled car's velocity are vx = 0.5 m/s and vy = 1.2 m/s. Find the components of the car's

FinnZ [79.3K]

Answer:

x-component of velocity = 5.7 m/s

y-component of velocity = -1.4 m/s

Explanation:

Use first equation of motion to find components of velocity at a given time:

$v = u + at$

where, $v$ is the final velocity, $u$ is the initial velocity, $a$ is the acceleration and $t$ is the time.

Given:

$u_x= 0.5 m/s\\u_y=1.2 m/s\\a_x=2 m/s^2\\a_y=-1m/s^2\\t = (2.6-0)s =2.6 s$

$v_x=u_x+a_xt\\\Rightarrow v_x=0.5+2\times 2.6\\\Rightarrow v_x=5.7 m/s$

$v_y=u_y+a_yt\\\Rightarrow v_y=1.2-1\times 2.6\\\Rightarrow v_y=-1.4 m/s$

5 0

2 years ago

A 150kg motorcycle starts from rest and accelerates at a constant rate along with a distance of 350m. The applied force is 250N

mart [117]

Answer:

205N

Explanation:

The net force (F) is the difference between the applied force( $F_{A}$ ) and the kinetic frictional force( $F_{R}$ ). i.e

F = $F_{A}$ - $F_{R}$ -----------------(i)

Note that;

$F_{R}$ = μmg

Where;

μ = coefficient of kinetic friction

m = mass of the body

g = acceleration due to gravity = 10m/s²

Equation (i) then becomes;

F = $F_{A}$ - μmg -------------------(ii)

<em>Given from question;</em>

m = mass of motorcycle = 150kg

μ = 0.03

$F_{A}$ = 250N

Substitute these values into equation (ii) as follows;

F = 250 - (0.03 x 150 x 10)

F = 250 - (45)

F = 205N

Therefore, the net force applied to the motorcycle is 205N

3 0

2 years ago

Bullets from two revolvers are fired with the same velocity. The bullet from gun #1 is twice as heavy as the bullet from gun #2.

IrinaVladis [17]

Answer:

option C

Explanation:

Let mass of the bullet be m and velocity be v

mass of gun be M and bullet be V

now,

using conservation of momentum for gun 1

(M+m) V' = 2 mv + 3 MV

V' = 0

3 M V = - 2 mv

momentum of gun 1 =- 2 mv---------(1)

now for gun 2

(M+m) V' = mv + MV

V' = 0

M V = - mv

momentum of gun 1 = -mv-----------(2)

dividing equation (1) by (2)

$\dfrac{P_m1}{P_m2} = \dfrac{- 2mv}{-mv}$

$\dfrac{P_m1}{P_m2} = \dfrac{2}{1}$

the correct answer is option C

7 0

2 years ago