One ball is thrown upwards at 10 m/s, the other is thrown straight down (not dropped) also at 10 m/s. Which ball arrives first? This is more of a theoretical question than anything. I know the relevant equations such as v^2=u^2 +2as, but I was thinking that the height of the building has to count for something because the ball travelling straight upwards would gain gravitational potential energy. But "common sense" dictates that the ball thrown straight down would arrive at the floor first.