This theory always gets the better of me when i have nothing else to think about....and it still baffles me...

If you stand on the top deck of a double decker bus and jump whilst the bus is in motion...you land in the same place on the bus....except you and the bus would have moved forward.

However if you stood on the roof and jumped YOU would be in the same place as when you jumped but the bus would have moved forward.

I hope i explained that well.....

Im sure its all about velocity or something..but it still baffles me....

Zara xx