Inertia is defined as the resistance to acceleration, and the Earth is considered a non-inertial frame of reference because it exerts an upward force on objects, preventing them from following a free-fall trajectory. While standing on Earth's surface, one is not in an inertial frame due to this gravitational influence. However, in specific contexts, such as high-energy particle physics experiments, the effects of gravity can be negligible, allowing the Earth to be treated as an inertial frame. Conversely, in scenarios like observing fluid interactions, gravity's impact must be accounted for, necessitating a different reference frame, such as a free-falling tank in space. Overall, the classification of Earth's frame depends on the context of the experiment or observation being conducted.
