Aprojectile leaves a rock that is 5 meters high, with a horizontal velocity of vox= 15m/s. calculate the time the projectile is in the air. sorry for the wording, this is what i could write down during class. p. s vox is v-not of x or initial velocity x, since it says it has an "horizontal" velocity. my professor used the equation y=yo + vo(t) - 1/2(g)(t^2) which is 0 = 5 + (0)t - 1/2(9.8)(t^2). my professor got 1 second for the answer, but i don't understand why he used 0 for initial velocity, when i thought initial velocity was 15m/s and final velocity 0. any is appreciated, !