CHAPTER 35 : EINSTEIN'S THEORY OF SPECIAL RELATIVITY
35.1 Frames of References
The motion of an object can be described with reference to a reference frame only. Without the
reference frame the description of motion is meaningless.
The laws of motion however should be such as to remain the
same when the transformation change over is made from one to another
reference frame, otherwise the laws are not universally capable
of explaining motion. If the laws remain same under transformation
from one to another reference frame then they are said to be 'invariant'.
Inertial Frames of References
Any frame of reference (co-ordinate system) in which the law of inertia holds good is called the
inertial frame of reference.
Non- inertial Frames of References
If the law of inertia does not hold good in the given frame
of reference i .e. the objects can be accelerated without real forces
being applied to them or can be in state of uniform motion when
real forces are applied then such a frame is called non- inertial
frame of reference.