Question

What is the source of centripetal force that a planet requires to revolve around the Sun? On what factors does that force depend?

Answer 1

Step 1. Centripetal force :

1. It is defined as the force that makes a body follow a curved path.
2. Its direction is orthogonal to the motion of the body and towards the fixed point of the center of curve path.
3. Its mathematical expression is $F_c=\frac{m{v}^2}{r}$, where $F_c$ = centripetal force, $m$ = mass, $v$ = velocity, $r$ = radius of curved path.
4. The SI unit of centripetal force is Newton.

Step 2. An illustrative diagram of the centripetal force :

Step 3 .Explanation :

1. The gravitational force applied by the sun on the planet is the source of centripetal force that a planet requires to revolve around the Sun.
2. This gravitational force depends on following factors :

2.1 Masses of objects : Gravitational force between two objects is directly proportional to the masses of the objects.

2.2 Square of the distance between the objects : Gravitational force between two objects is inversely proportional to the square of the distance between the objects.