Question

What are inertial frame of refrence? How it has been established that earth is not an inertial frame.

Answer 1

In physics, an inertial frame of reference (also inertial reference frame or inertial frame or Galilean reference frame or inertial space) is a frame of reference that describes time and space homogeneously, isotropically, and in a time-independent manner.[1]

All inertial frames are in a state of constant, rectilinear motion with respect to one another; an accelerometer moving with any of them would detect zero acceleration. Measurements in one inertial frame can be converted to measurements in another by a simple transformation (the Galilean transformation in Newtonian physics and the Lorentz transformation in special relatI've. Is it right

Answer 2

An inertial frame of reference is a frame of reference in which Newton's Laws of motion hold good. According to Newton's 1st Law, a body retains its state of rest of motion in absence of external forces. Now a body that is at respect with say a frame of reference, S then it necessarily may not be at rest with respect to another frame S'. For example a boy standing in a lift going up with some acceleration a, according to his frame of reference, he is at rest but according to someone from outside the lift the boy is going up with acceleration a, so there are external forces acting on the boy according to someone outside the lift, so newton's laws will fail spectacularly. Similarly due to the rotation and revolution of earth, external forces like coriolis force and centrifugal forces act on the earth, so the earth is not an inertial frame of reference. Simply put an inertial frame of reference is a frame of reference that is not accelerating with respect to another inertial frame of reference, a frame of reference moving with constant velocity with respect to an inertial frame of reference is also an inertial frame of reference.

Answer 3

inertial in which accellration is zero none- inertia in which acc is not zero simple

Answer 4

"How it has been established that earth is not an inertial frame."

gravity. if you are in a sealed room on earth's surface or in a sealed room "accelerating" through "gravity-less" space, you will feel the same and your spring mass system will measure the same thing.

to be truly non-inertial, i think you would have to be in freefall, ie reacting perfectly to whatever gravity is affecting you.

so you can't just say that it is about acceleration.

in practical terms, a lot of the spesh rel mind experiments occur on earth but in the horizontal direction. so in practical terms you can talk about the moving train and the observor on the platform and the light clock that is typically moving in the vertical direction, without compromising the numbers.