1. The problem statement, all variables and given/known data Which one of the following statements is true concerning the motion of an ideal projectile launched at an angle of 45 degrees to the horizontal? ok so, it seems simple enough, this was a multiple choice questions and i narrowed it down to 2 solutions: 1) the speed at the top of the trajectory is zero. 2) the vertical speed decreases on the way up and increases on the way down. I got stumped here; both of them seem to be true, so when i looked in the answers it said that 2 was right because "the acceleration of the projectile is always down..[the rest of the answers] are wrong. I dont get this, anyone explain this better?