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.
Quick Answer. In projectile motion, horizontal velocity is the rate at which an object is traveling parallel to the earth. Scientists calculate horizontal velocity using the formula v = d/t, the same formula used to determine the speed of an automobile. In projectile motion, horizontal velocity does not change; however, the forces of gravity give the object vertical acceleration, causing it to stop when it hits the ground.