LifeinAsia - 8:35 pm on May 29, 2009 (gmt 0)
Wouldn't the locomotion of the train be considered an external force?
Nope- no acceleration, so no external force. Except for gravity, which is pulling it downwards.
the golf ball will begin horizontal deceleration
Nope- there is no force decelerating it.
our happy experiment is abruptly halted due to the failure of our myopic engineers to account for that tunnel.
Or the failure of the engineers to account for the lack of a tunnel. SPAT! :)