Question

A projectile 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 help is appreciated, thanks!

Answer 1

Your professor is correct. He / She used zero because that is where the objects starts to decrease and it starts to fall.