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A Question From Relativity

Sreeram Asks:

“my question is on relativity.Let us say two persons,one is standing still and other is moving with uniform velocity in a straight line(in +ve x direction),both are carrying  a clock synchronized previously.For the moving person he is at rest and the other guy is moving away from him in the opposite direction(negative x direction).Both of them feel that clock of the other guy is moving slowly.let us say the moving guy never stops and he calls the other in telephone at some point of time and asks the
time in his clock.But he will find that clock with him,is actually faster.how can that happen?”


Please note that the theory of relativity can  be applied only for velocities compared to that of light in vacuum (3 lakh km/s). The situation will be very much different when we travel at such velocities. So far we are able to accelerate only subatomic particles to this speeds (LHC).




  1. I am not so clear about your question.What I so far learnt from my limited exposure to Relativity is that time tends to slow down as the speed increases.There isn’t a law stating the reason.But the fact is that it is done in order to maintain a barrier on the speed so that we don’t exceed the speed of light !It’s a law of nature.Since we really don’t understand what really would happen once we accelerate to that speed,answer this ques wud indeed be a little tricky(@ least for me) 🙂 !

  2. i think
    the case presented by you is possible only when one is moving towards an object
    for example:
    if you are going towards a planet at a speed of 0.8c(80% speed of light) the clock at the planet would never be faster but ahead of you.

  3. my question is about power problem
    what horse power? is used when an engine pulls a train with a force of 200N,and 96Km/hr.

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