- #1

magicuniverse

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## Homework Statement

a ufo travels from one planet to another (distance measured 384000km) at v=0.8c.

1)How long does the trip take according to observer on planet left?

2)How long does the trip take according to observer in ufo?

3) What is the two planets distance measusured my aliens in the ufo?

## Homework Equations

I think I have to use the lorrentx transformations.

t'=alpha(u/c)(t-ux/c^2)

t=alpha(u/c)(t'+ux'/c^2)

x=alpha(u/c)(x'+u't)

## The Attempt at a Solution

This is my first ever SR question I have done. So I wasnt sure.

I thought that from the original planet the apparent velocity is going to be 0?

so i said the time takes was = 1.83 s?

So then i said using the above formula that alien man thought it would be = 2.69s

As this is wrong I havnt proceeded to the next part. Can you please tell me where i am going wrong and possibly give me some advice as to how to set up these types of questions.

thanks