Answer:
V = a t formula for change in velocity due to acceleration
Vy = ay t would be the formula for the "downward" vertical velocity due to a downward acceleration such as g = 9.8 m/s^2
Suppose an object is projected upwards with a velocity VY0 then
Vy = Vy0 - a t = Vy0 - g t for the vertical speed at a time t
