brass's favorite notices, page 3

William Henry Nillson (WillyNilly)

♪♫ All you gotta do is take a spoon of sugar, pour it in the cup~ ... stir in a little bit of cream or milk to fill the whole thing up~ ... makin' this drink is such a treat, drink it with some toast and jelly~ ... pour me some more, better drink it before ... It all is in my belly! Coffee, warm and delicious! Coffee, not too nutritious! Coffee! COFFEE-COFFEE-COFFEE!!!!

aaaaaaaaaa

All that math this morning has gotten me worked up, so I imagined this fun scenario: Rainbow Dash has fallen prey to one of Pinkie Pie's diabolical pranks! Due to a paint-related mishap, her light-blue coat is now dyed green (lambda_1 = 510 nm). Not wanting to be seen in this state by you, the diligent stationary observer, she races in a straight line towards you, in an attempt to blue-shift her coat back to its original light-blue colour (lambda_2 = 480 nm). How fast must she fly in order to have you perceive her coat as its original colour? Assume Doppler shifting in flat spacetime. (For reference, the answer that I worked out is 1.8 x 10^7 m/s - much faster than the required speed for a Sonic Rainboom!).

Ellis

I think I took care of all the spammers. There was like 10 of them :/