This phenomena is also called the Doppler shift. When the source of light is approaching towards an observer, the color tends to be blue shifted, but when the source is moving away or being stretch, the color tends to red shifted. In astronomy it can be use how fast galaxy is moving towards us or how fast it moves away.
According to the <u>Third Kepler’s Law of Planetary motion</u> “<em>The square of the orbital period of a planet is proportional to the cube of the semi-major axis (size) of its orbit”.</em>
In other words, this law states a relation between the orbital period
of a body (moon, planet, satellite) orbiting a greater body in space with the size
of its orbit.
This Law is originally expressed as follows:
<h2>

(1)
</h2>
Where;
is the Gravitational Constant and its value is 
is the mass of Jupiter
is the semimajor axis of the orbit Io describes around Jupiter (assuming it is a circular orbit, the semimajor axis is equal to the radius of the orbit)
If we want to find the period, we have to express equation (1) as written below and substitute all the values:
<h2>

(2)
</h2>
Then:
<h2>

(3)
</h2>
Which is the same as:
<h2>

</h2>
Therefore, the answer is:
The orbital period of Io is 42.482 h
Answer:
no material that were once part of living things
Answer: 154.08 m/s
Explanation:
Average acceleration
is the variation of velocity
over a specified period of time
:

Where:

being
the initial velocity and
the final velocity

Then:

Since
:

Finding
:


Finally:
