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Homework Help: Time dilation

  1. Dec 10, 2006 #1
    1. The problem statement, all variables and given/known data
    spaceship 3 meters wide, v= 2c/3. (a.) calculate ships time, (b) sq. root factor, (c) earth's time, (d) ships displacement, (e) lights displacement, and (f) which clock "runs slow"

    2. Relevant equations
    a. Ts=(3m)/c
    b. square root 1-v^2/c^2
    c. earth's time = answer a/b (it tells me to use the two formulas actually, i figured this is equivalent)
    d. ships displacement =vt
    e. lights displacement= ct
    f. which clock runs slow

    3. The attempt at a solution
    all of the formula have been given to me, i just wanna make sure my answers are right.
    a. 3m/3.00X10^8 m/s= 1X10^-8 s
    b. sq. root 1-2X10^8= -1.9999999X10^8
    c. t= -5X10^-17-----should this be a magnitude????
    d. 2c/3*-5X10^-17= -1X10^-8 meters
    e. ct= (3.00X10^8 m/s)(-5X10^-17) =-1.5X10^-8
    g. i think i remember from the lecture that the earth clock runs slow because of the displacement, it seems like it takes longer.

    like i said, i just wanna see if my work is right. i have a feeling c is wrong, because time shouldnt be negative. im pretty sure the formulas are right because my teacher gave them in the book.
  2. jcsd
  3. Dec 11, 2006 #2


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    Your problem statement is a bit vaque to say the least. What times are you talking about? Is 3m is the rest length of the ship?
  4. Dec 11, 2006 #3
    I honestly don't know. Everything I was given I put in the problem word for word. But it's ok anyways, I took my final today and this problem wasn't on there, but it is kind of annoying that I can't figure it out.
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