Imagine that you are in an inertial frame in empty space with a clock, a telesco
ID: 2252412 • Letter: I
Question
Imagine that you are in an inertial frame in empty space with a clock, a telescope and a powerful strobe light. A friend is sitting in the same frame at a very large (unknown) distance from your clock. At precisely 12:00:00 noon according to your clock you set off the strobe lamp. Precisely 30 s later you see in your telescope the face of you friend's clock illuminated by your strobe flash. How far away is your friend from you? What should you see on the face of the clock if the clock is synchronized with yours? Why?
Explanation / Answer
both are in same inertial frame means both aren't moving
30 sec round trip means light spends 15 seconds getting there and 15 seconds coming back
s=15*c where is speed of light
so s=15*3*10^8=45*10^8 metres
clock reads 15 seconds after 12.