Answer:
a) M = 2 10³⁰ kg
, b) 
= 5.81 10⁷ s
Explanation:
a) For this exercise let's use Newton's second law where force is the law of universal gravitation and acceleration is centripetal
G m M / R² = m a
a = v² / R
G M / R = V²
The orbit of the two planets is approximately circular, therefore the velocity module (speed) is constant
v = d / t
The distance is the length of the circular orbit
d = 2π R
G M / R = 4π² R² / T²
G M T² = 4π² R³
Let's write this equation for each planet
For the earth
The period is T = 3.16 10⁷ s and the radius of the orbit R = 1.5 10¹¹ m, let's calculate the mass of the sun
M = 4π² R³ / G T²
M = 4π² (1.5 10¹¹)³ / (6.67 10⁻¹¹ (3.16 10⁷)²)
M = 133.24 10³³ / 66.60 10³
M = 2 10³⁰ kg
b) For this part we write this equation for the two points
For the earth
² = (4π² / G M) 
³
For mars
² = (4π² / G M) 
³
Let's divide the two expressions
² / ² = ³ / ³
They indicate that the orbit of Mars is = 1.5
² / ² = (1.5 / )³
² = ² 1.5³
² = (3.16 10⁷)² 1.5³
= √ (33.70 10¹⁴)
= 5.81 10⁷ s
In one of the most amazing coincidences in all of science,
the part of the electromagnetic spectrum that's visible to the
human eye is called "visible light".
Visible light is not 'divided' into anything. We mention the names
to seven of the colors in visible light. But all of the thousands of
OTHER colors that we can see are in there too, even though we
don't bother to list their names when we buzz through the rainbow
in the third grade.
The Bohr model of atom addressed the problem of why electrons did not fall into the positive nucleus.
As per Rutherford's atomic model, electrons are revolving around the nucleus just like planets are revolving around the sun. But his description about electronic motion was against the Clark Maxwell's electromagnetic theory .
As per Maxwell any charged particle under accelerated motion will release energy. The electron is a negatively charged particle which under acceleration will come closer and closer to the nucleus and finally it will fall on the nucleus for which the whole atom will be destroyed. The path of electron will be a spiral one instead of circular. Hence Rutherford's theory could not explain the stability of nucleus.
Bohr addressed that electron in particular orbit has a fixed amount of energy .There will be no emission or absorption of energy as long as electron revolves around the nucleus.The electron will absorb energy when it will jump from ground state to excited state and will emit energy when it will jump from excited state to ground state.
Hence the option A is right,.
An experimental variable is a variable that is being tested to answer a scientific question; while a control variable is a variable that is not being altered or changed during the experiement to serve as a constant. An example of an experimental variable is plant food solution A and whether it makes a kidney bean sprout faster than plant food solution B. An example of a control variable is water, because there is no plant food mixed in to create a solution; so it will serve as a natural constant.
The correct answer is: Crescent moon.
I hope this helps you!
Brainliest answer is always appreciated!
