Kids at the neighbourhood are harrassing Superdog. While Superdog sleeps outside his cabin, the brats tie an empty tin can to his tail. After doing this, they drop the tin can, which makes a clanking noise, and scares out Superdog.
Superdog starts to run at 2 km/h. The tin can bounces from the ground and hits the ground after 3 seconds and makes another clanking noise. The noise scares Superdog even more and makes him double his speed (the fact that he can do it is obviously why he's called the Superdog).
New clanks will follow at 3 second intervals, and upon hearing each clank Superdog doubles his speed. What is Superdog's velocity after 35 seconds have passed from the initial clank?
Published in Njet Problem! collection 1996-01-31.