I'm creating a pneumatic launching device to shoot projectiles vertically. I guess the closest thing to compare it to would be a regular gun. Once it leaves the barrel, it will be in a constant state of deceleration until it reaches its peak (no additional thrust provided). Ignoring frictional losses, is there a systematic way to calculate the projectiles rate of deceleration? Does the weight matter (i.e. will a tennis ball and a bowling ball decelerate at the same rate)? Does the exit speed matter? Ideally I would like to take a projectile, knowing the force provided by the pneumatic actuator and the weight of the projectile, calculate exactly how high the projectile will go. Then once I've mastered calculating it in a frictionless environment, put it in a wind tunnel and calculate losses due to friction. Also, just a general question somewhat related, in an environment with friction, will it take the exact same amount of time to reach ground-to-peak as peak-to-ground?