Hi everyone.(adsbygoogle = window.adsbygoogle || []).push({});

Right now, I'm studying time dilation. I think I understand the thought experiment which involved a laser reflecting from a mirror in a train car, (Page 15 of Modern Physics, Serway, Moses, Moyer) and the derivation of

[tex]\Delta t = \gamma \Delta t_p[/tex]

using a right triangle.

My problem is, I made up a different (most probably flawed) thought experiment, through which I cannot arrive at the same formula. Here it is: There is a stationary observer in O, who has a light source which emits in +x direction, and I call his reference frame S. There is another observer in O, with a constant velocity u in +x direction. Call his reference frame S'. Now, after [tex]\Delta

t[/tex] time for a clock in S, the second observer has moved [tex]u \Delta t[/tex], the light [tex]c \Delta t[/tex]. So, the light went [tex](c - u)\Delta t[/tex] according to the observer in S'. If [tex]\Delta

t'[/tex] is the time passed in S', [tex]\frac{(c - u)\Delta t} {\Delta t'} = c[/tex] because the observer in S' should see the speed of light as c too. But this is not equivalent to [tex]\Delta t = \gamma \Delta t_p[/tex] mathematically. What am I missing here?

Thank you.

(I'm not experienced with LaTeX, so I will edit the post until the tex code is correct.)

**Physics Forums - The Fusion of Science and Community**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Question About Time Dilation

Loading...

Similar Threads for Question Dilation | Date |
---|---|

B Speed of light, Time Dilation Question. | Jan 23, 2018 |

B Question about time dilation | Jan 5, 2018 |

B Time dilation and length contraction question | Jan 28, 2017 |

I Time Dilation Questions | Nov 24, 2016 |

B Time dilation problem question | Nov 18, 2016 |

**Physics Forums - The Fusion of Science and Community**