In the case of acceleration always in the direction of the motion and the direction of motion should be in positive or negative, the angle between the vectors (α) is 0, so cos ⁡ ⁡ 0 = 1 , and | v | 2 = | v 0 | 2 + 2 | a | | r − − r 0 | . This can be simplified using the notation for the magnitudes of the vectors | a | = a , | v | = v , | r − − r 0 | = Δ Δ r where Δ Δ r can be any curvaceous path taken as the constant tangential acceleration is applied along that path, so v 2 = v 0 2 + 2 a Δ Δ r .