Question

What is the work done by the moon when it revolves around the earth?

Answer 1

Hint Displacement means how far an object is and it is the overall change in the position of the object. So by keeping this in mind we can think about what work is being done by the moon when it revolves around the earth.

Complete step by step answer:
As we already know the moon revolves around the earth in a uniform circular motion. This means that the moon will have a constant speed and the radius of the moon will be fixed. So if the moon is in a uniform circular motion then its speed will not change.
As in one revolution, the moon comes back to its initial position the position from where it started and the displacement will be zero.
Let us think the earth is a nucleus and the moon is like electrons revolving around it. Same as an electron does not work on the nucleus or we can say there is no attraction from the nucleus for an electron.
Also, we know
Work is equal to the force along the displacement having the theta angle.
Mathematically we can write it as,
$ \Rightarrow W = F \times d{\text{ }}.{\text{ cos}}\theta $
Where $W$ is the work done, $F$is the gravitational force between earth and the moon, $d$ is the displacement of the moon, and $\theta $is the angle between force and displacement.
As here $\theta $ is ${90^ \circ }$.
By putting the values,
$ \Rightarrow W = F \times d{\text{ }}.{\text{ cos9}}{{\text{0}}^ \circ }$
And on solving the above equation
$ \Rightarrow W = F \times d{\text{ }}.{\text{ 0}}$
$ \Rightarrow W = 0$

Since the work is done is zero so we can say that the work done by the moon when it revolves around the earth is zero.

Note: Centrifugal force is an outward force apparent during a rotating organization. It doesn't exist once a system is delineated relative to a reference system. The concept of force is applied in rotating devices, like centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in centrifugal railways, planetary orbits, and banked curves, once they are analyzed during a rotating reference frame.