damn dude, I'm going to be thinking about his all day now
If there's no wind resistance, then the test would be done in a vacuum, and that makes it all the more complicated
I'd say that even though the truck is moving at 55mph, and the launcher launches the ball at 55mph, muzzle velocity decreases over distance, so even though the truck is moving at the same rate as the ball in the exact opposite direction, the ball will slow down over its trajectory path, whereas the truck will not, so the ball will still land past the line. Even though the ball may not be moving in terms of its relation to the ground, its reference for distance is the object of which it was launched
from, not landing
on. I had to analyze something like this in terms of SAMs and Airborne Weapons Systems before, so I'm biased
And I'm assuming we are guessing where the ball will
land and not take into consideration the ball rolling, and the levelness of the floor of which it lands