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## Homework Statement

A meter ruler moves at velocity u to the right past a stationary observer. The observer is at (0,0) in his rest frame. Give the (x,t) co-ordinates of the following events.

1. The right end of the ruler passes the observer (in the observer's frame)

2. The left end of the ruler passes the observer (in the observer's frame)

3. The observer passes the right end of the ruler (in the ruler's frame)

4. The observer passes the left end of the ruler (in the ruler's frame)

## Homework Equations

t2 = [itex]gamma[/itex]*(t2 dash + u * x2 dash / [itex]c^2[/itex])

x2 = [itex]gamma[/itex]*(x2 dash + u * t2 dash)

Where the dashed co-ordinates are in the ruler's rest frame.

## The Attempt at a Solution

1. The right end of the ruler passes the observer (in the observer's frame) (0,0)

2. The left end of the ruler passes the observer (in the observer's frame) (0,t2)

3. The observer passes the right end of the ruler (in the ruler's frame) (0,0)

4. The observer passes the left end of the ruler (in the ruler's frame) (-1,t2 dash)

which when I use the above equations I get t2 dash = 1/u

Where have I gone wrong?

PS Not sure how you get subscripts and dashes in LaTex