Question

A planet takes three years to complete the
orbit around the sun. Its orbe is coplanar
with that of earth. What is the time taken by
the planet to complete the orbit around the
sun as observed from the ear?​

Answer 1

Answer:

The question says three years!

Explanation:

Answer 2

Given:

• The time that is taken by the planet to complete an orbit around the sun = 3 years.

To Find:

• The time that is taken by the planet to complete the orbit around the sun when observed from the earth.

Solution:

The formula is given by,

$T_{relative}=T_{planet}-T_{earth}$  → {equation 1}

Here the time taken by the earth to complete one revolution around the sun is one year or 365 days.

On substituting the values in equation 1 we get,

⇒ $T_{relative}$2 years. {subtracting the terms}

In the above step, we found the time taken by the planet to complete one orbit around the sun when observed by the earth, this is the reason why we are introducing earth's time in equation 1 and subtracting that from the planet's time.

∴ The time that is taken by the planet to complete the orbit around the sun when observed from the earth = 2 years.