08 June 2007
For your entertainment, on the page I found it, it said "Vector physics in real life. From 'Trivia no Izumi' (Fountain of Trivia), the same Japanese show that figured out how heavy a fish Dora cat can carry."
For your edification, what's happening is the truck is driving forward (left) at 100km/hr, while the ball is being shot backwards (right) at (-)100km/hr relative to the truck. Note in particular the strobe effect photos of the ball shot from a stationary truck at 1:40, and the ball shot from the moving truck at 3:50. Also note that while the ball falls it drifts forward slightly, this could be due either to a mismatch in velocities or due to drafting (wind following the motion of the truck), and after it impacts the ground it bounces forward significantly, probably due to spin ("English") on the ball or possibly due to drafting (since the video is sped back up we can't tell how fast it's moving forward compared to while it was falling).
Link c/o hitchhiker.