Well, this would depend on whether Ed is standing inside the moving
bus or on the ground in front of the bus. Since I can't quite tell
which you mean, I'll answer both questions.
If Vince is on the ground in front of the bus then the answer will
depend on just how fast 'really really fast' is for the bus and just
how high 'really really high' is for Vince. While Vince is up in the
air, the bus is moving underneath him. If the bus is going too fast,
then it will move all the way out from under him before he comes down.
Similarly, if he jumps too high, then by the time he comes down again,
the bus may already be out of the way. But if he managed to get his
jump to just the right height and/or the bus was going at just the
right speed, then... sure, Vince could land on the bus.
Whether or not he could stay on the bus is a whole 'nother issue.
This is because the bus has momentum going forwards and Vince doesn't.
So even after he's landed on the bus, the bus could still 'drive out
from under him', making him slide off the back.
If Vince is standing in the bus when he jumps this means he is
moving with the same velocity as the bus when he jumps, and will land
exactly where he started from on the bus (unless the velocity of the
bus happens to change while Vince is in the air).
(republished on 07/11/06)