The purpose of the two studies presented in this paper is to establish validity evidence for the Sport Multidimensional Perfectionism Scale-2 (Sport-MPS-2: Gotwals & Dunn, 2009). Studies 1 and 2 are respectively focused on the production of structurally-related and external validity evidence.
The horizontal velocity of a projectile is constant (a never changing in value), There is a vertical acceleration caused by gravity; its value is 9.8 m/s/s, down, The vertical velocity of a projectile changes by 9.8 m/s each second, The horizontal motion of a projectile is independent of its vertical motion.
Vertical means up and down; so the vertical velocity is an indication of how quickly an object is rising or falling. If the object is moving at an angle (such as an airplane taking off or landing) then it would be more accurate to call it the vertical component of the object's velocity. Aries Dell.