# Time dilation years of trip

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1. Feb 22, 2016

### persephoneia

1. The problem statement, all variables and given/known data
Suppose you decide to travel to a star 65 light-years away at a speed that tells you the distance is only 25 light-years. How many years would it take you to make the trip?

2. Relevant equations
∆t=∆t0/(√ (1−v2/c2 )) / ∆t0 = ∆t √(1−v2/c2)
L=L0√ (1−v2/c2)

3. The attempt at a solution
I've attempted to use the length contraction equation to find the velocity (v=c√(1-(25/65)^2) but when I plug that into the time dilation equation I don't get the correct answer. I get 25 when the answer should be 27. Where am I going wrong?

2. Feb 22, 2016

### PeroK

If you know the distance in your frame and the velocity in your frame, what do you need time dilation for?

3. Feb 22, 2016

### persephoneia

I don't. I wasn't thinking that light years is also a distance because I looking at an example for the problem that combined the two equations (length contraction & time dilation) which threw me off. It's basically t=d/v after you figure out velocity right?

4. Feb 22, 2016

### PeroK

Right!

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