This question already has an answer here:
We all know the following universal truth since childhood.
Earth (and other planets) orbits around the Sun.
And, while I was reading this post, I found that the reason behind Earth revolution is chiefly due to one force:
Some physicists explains the movement of Earth around the Sun on the basis of the following image:
As we can see, the initial state of rock is rest. And when we apply a force, it starts moving in a circular path.
Now my question is from where the Earth had got the inertia of motion? As the rock in the above example was initially at rest and so the Earth should also be in state of rest (without any force applied on it).