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Specialy theory of relativity

  1. Mar 12, 2008 #1
    what effect would increasing the speed of the spacecraft have on the astronaut's pulse as measured by the astronaut and by the earth observer? why. I think in both measurements, an increased pulse rate will be found?..
     
  2. jcsd
  3. Mar 12, 2008 #2
    The pulse is only an example of a clock in general. Any type of clock. You can look for a description in the textbook that probably phrases it as "the rate that time passes" or the "the speed of a clock", in one frame of reference, compared to another frame of reference. Consider which frame of reference undergoes acceleration.
     
  4. Mar 12, 2008 #3
    the question is refering to heart beat..per min.
     
  5. Mar 12, 2008 #4

    Dick

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    As mikelepore said, it's the same thing as the rate of a clock.
     
  6. Mar 13, 2008 #5
    so...the astronaut will observe ...her pulse being slowed down?....:Sstill confused
     
  7. Mar 13, 2008 #6
    Maybe you have a formula for an interval of time as it is measured by different observers, some formula that begins: t = ......
     
  8. Mar 13, 2008 #7
    t=to/(sqrt1-v^2/c^2)
     
  9. Mar 13, 2008 #8
    You have two people, an astronaut and an earth observer. You also have two times, t and t0. Your textbook must explain how to assign which to which. In fact, most books use a traveler on a spaceship as the author's favorite example. Then you have the astronaut moving at speed v, which is less than c. That sqrt is in the denominator and not the numerator, and that must have some effect the answer.
     
  10. Mar 13, 2008 #9

    Dick

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    v is the relative velocity between the observer and the observed. The astronaut isn't moving relative to herself. In that case v=0.
     
  11. Mar 13, 2008 #10
    I know. but in general ..what happens? when the speed of the spacecraft is increased. will the earth based observer's measurement be more beats per min or less than b4? and what about astronaut, will she experience the frequency of her pulse to be more or less than b4?
     
  12. Mar 13, 2008 #11

    Dick

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    If you say "I know.", what is it you know? Will the speed increase change the speed of the astronaut relative to herself? For the other question what does your formula t=to/(sqrt1-v^2/c^2) tell you? t0 is the rest frame interval (and it's fixed). t is the observed interval. Does t get bigger or smaller as v approaches c?
     
  13. Mar 13, 2008 #12
    t gets bigger...
     
  14. Mar 13, 2008 #13

    Dick

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    Good. Now what does that tell you about the original question? t0 is the interval between beats measured by the astronaut. t is the interval between beats measured from earth.
     
  15. Mar 13, 2008 #14
    to is same while t increases....?
     
  16. Mar 13, 2008 #15

    Dick

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    t0 is the interval between beats that the astronaut herself measures. That doesn't depend on v, right? Right? You said "I know". I remember.
     
  17. Mar 13, 2008 #16
    righttt........i think i said i know to somthing else....
     
  18. Mar 13, 2008 #17

    Dick

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    I'd be curious what that something is. A moving observer never observes her own heart beating slow or her own clocks running slow. She can consider herself 'at rest'. At v=0. That's why it's called the "Specialy theory of relativity". Every observer can consider their own time reference as unchanging.
     
  19. Mar 13, 2008 #18
    i was replying to someone else..when i said "i know" lol....i finally get it ....:)
     
  20. Mar 13, 2008 #19
    thankyou
     
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