Question

Name the source of the centripetal force that the earth requires to revolve around the sun. Derive an expression for this force.

Answer 1

1. The force that makes an object move in a circular path by constantly changing its direction and velocity around a fixed point is called the centripetal force.
2. Here, the earth is moving in a circular path around the sun.
3. The source of the centripetal force that the earth has got to revolve around the sun is the gravitational force of the sun.
4. The magnitude of the gravitational force (F) exerted by the sun on the earth is given by $F=\frac{GMm}{R^2}$, where G is the universal gravitational constant, M is the mass of the sun, m is the mass of the earth and R is the distance between them.