How fast am I moving..?

I'm in a commercial airplane - travelling from here to there, west to east.  I get up and walk from row 20 to row 2 going towards the front of the cabin.   I'm moving at 2mph down the aisle.  The aircraft is travelling over the earth at 500 mph.

How fast am I moving ?

The answer may be selected from the options below..

1)  I'm moving at 2mph
2)  I'm moving at 502 mph
3)  I'm moving at 18mps (where s = seconds)

Which is it..?









Look down here once you select an answer..




The answer, which may surprise you is that all three answers are equally correct, and the answer you arrive at depends 100% on your perspective.

I am moving at 2mph down the aisle, and if in the cabin of the aircraft with me, that's the correct answer.  To an observer on the ground, the aircraft is travelling overhead at 500mph, and if they knew I was moving in the same direction as the plane while onboard, they would conclude I was moving at 502mph.  That's the correct answer from that position.  To an observer standing on the Sun, (very warm feet) the movement I'm making and the aircraft too for that matter are a rounding error on the earth's rotation.  To them, i'm moving at 18 miles per second.  For them, that's the correct answer.

How can all answers be equally correct ?  It's because I never stipulated where you were in asking the question.  So you have to understand you are in any location.  For that matter, there are other answers if we locate you in the Andromeda Galaxy and ask for the observations from there, and so on.  I think you get the point though.

Perspective rules.  Remember to acknowledge that.