Third Equation of Uniformly Accelerated Motion
The third equation is used in a situation when the acceleration, position and initial velocity are known, and the final velocity is desired but the time t is not known.
x – x0 = ½(v + v0)t
t = (v - v0)/a
x – x0 = ½(v + v0)(v - v0)/a
2a(x – x0) = v2 – v02
v2 = v02 + 2a(x – x0)