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Urgent Help! Time Dilation

A team of astronauts set off from a stationary space station at one quarter of the speed of light. They are carrying a highly accurate atomic clock. They travel to another space station, stationary with respect to the first one , and which is one quarter of a light year away from the first one. They immediately turn round and travel back to the original space station, at half the speed of light. How much time has elapsed on the atomic clock ? How does this compare to the time elapsed on the space station ?

Therefore I know for the first journey v=0.25c x=0.25 light years.
The return journey is v=0.5c and x=0.25 light years.

I know I have to find the time but Im confused as to which formula to use please help guys exam in afternoon! :frown:
Reply 1
Anyone? :frown:
Reply 2
Special Relativity states:

tactual=texperienced1v2c2 t_{actual} = \dfrac{t_{experienced}}{\sqrt{1-\frac{v^2}{c^2}}}

Now then for the first part, the time it takes is exactly one year, so:

tactual=3.15×107 t_{actual} = 3.15 \times 10^7

Put the numbers into the equation:

texperienced=3.15×10710.25212=3.05×107s t_{experienced} = 3.15 \times 10^7 *\sqrt{1-\frac{0.25^2}{1^2}} = 3.05 \times 10^7 s

For the second part of the journey, the time it takes is half a year, so:

tactual=1.58×107 t_{actual} = 1.58 \times 10^7

Again into the equation:

texperienced=1.58×10710.5212=1.37×107s t_{experienced} = 1.58 \times 10^7 *\sqrt{1-\frac{0.5^2}{1^2}} = 1.37 \times 10^7 s

Overall time =
4.42×107seconds 4.42 \times 10^7 \text{seconds}
(edited 10 years ago)
Reply 3
Is that overtime for the atomic clock?
Original post by Piguy
Special Relativity states:

tactual=texperienced1v2c2 t_{actual} = \dfrac{t_{experienced}}{\sqrt{1-\frac{v^2}{c^2}}}

Now then for the first part, the time it takes is exactly one year, so:

tactual=3.15×107 t_{actual} = 3.15 \times 10^7

Put the numbers into the equation:

texperienced=3.15×10710.25212=3.05×107s t_{experienced} = 3.15 \times 10^7 *\sqrt{1-\frac{0.25^2}{1^2}} = 3.05 \times 10^7 s

For the second part of the journey, the time it takes is half a year, so:

tactual=1.58×107 t_{actual} = 1.58 \times 10^7

Again into the equation:

texperienced=1.58×10710.5212=1.37×107s t_{experienced} = 1.58 \times 10^7 *\sqrt{1-\frac{0.5^2}{1^2}} = 1.37 \times 10^7 s

Overall time =
4.42×107seconds 4.42 \times 10^7 \text{seconds}
Reply 4
Also how did you the the T actual value?
Original post by Piguy
Special Relativity states:

tactual=texperienced1v2c2 t_{actual} = \dfrac{t_{experienced}}{\sqrt{1-\frac{v^2}{c^2}}}

Now then for the first part, the time it takes is exactly one year, so:

tactual=3.15×107 t_{actual} = 3.15 \times 10^7

Put the numbers into the equation:

texperienced=3.15×10710.25212=3.05×107s t_{experienced} = 3.15 \times 10^7 *\sqrt{1-\frac{0.25^2}{1^2}} = 3.05 \times 10^7 s

For the second part of the journey, the time it takes is half a year, so:

tactual=1.58×107 t_{actual} = 1.58 \times 10^7

Again into the equation:

texperienced=1.58×10710.5212=1.37×107s t_{experienced} = 1.58 \times 10^7 *\sqrt{1-\frac{0.5^2}{1^2}} = 1.37 \times 10^7 s

Overall time =
4.42×107seconds 4.42 \times 10^7 \text{seconds}
Reply 5
Original post by mathslover786
Also how did you the the T actual value?


Speed = Distance * Time,
you can just cancel out the speed of light parts, so you end up with a year, and half a year respectively...

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