How do you solve free fall problems solving kinematic equations?

Like any moving object, the motion of an object in free fall can be described by four kinematic equations. The kinematic equations that describe any object's motion are:

D = vit + 1/2 at2    

(vi +vf)/2 = D/t

a = (vf - vi)/t          

vf2 = vi2 + 2aD

D = displacement

a = acceleration

t = time

vf = final velocity

vi = initial velocity

Explanation:

Free fall means that an object is falling freely with no forces acting upon it except gravity, a defined constant, g = -9.8 m/s2. The distance the object falls, or height, h, is 1/2 gravity x the square of the time falling. Velocity is defined as gravity x time.

The kinetic equation is the evolution equation of the distribution function. It is to the distribution function what Newton's second law is to an individual particle. It is deduced from this fundamental law. It has the following general form: ∂ t f + v .