s = displacement, v = mean velocity, t = time, u = initial velocity, a = acceleration

  The equations above govern the motion of bodies. The first equation states that the displacement of a body is equal to the mean velocity multiplied by the time of travel.

  The second equation, which is only valid for a constant acceleration a , states that the displacement is the sum of two terms. The first is the product of the initial velocity and the time of travel, and is equal to the distance that would have been travelled had the body been unaccelerated. The second term takes into account the extra displacement caused by the acceleration.