The Vertical Distance equation, Delta y= 1/2*a_y* Deltat^2, calculates the vertical distance traveled (Delta y) by an object from the origin after a period of time (t), the objects initial velocity and displacement are zero and a constant acceleration (a).
Note: this is a form of the following equation with no initial distance (x0= 0). dx = x_0 + v_0*t + 0.5*a*t^2
Acceleration (a) is typically - m/s2 to represent the negative (downward) force of gravity.