Question

"It is reasonable to consider the earth as an inertial frame for many laboratory scale terrestrial experiments, but the Earth is a non-inertial frame of reference for astronomical observation." Explain this statement. Do you see how the same frame of reference is approximately inertial for one purpose, and non-inertial for the other?

Answer 1

The earth revolves around the sun with some acceleration. So strictly, we can say that it is not an inertial frame of reference. But, for the bodies lying on the surface of the earth or very close to the earth, the earth can be considered as an inertial frame of reference.