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. 
             [next page] 
       |