The equation v=u+at is valid. It represents the relationship between the final velocity (v), initial velocity (u), acceleration (a), and time (t) in a linear motion. It is derived from the equation of motion: s = ut + (1/2)at^2, where s is the displacement. By rearranging this equation, we get v = u + at, which shows that the final velocity is equal to the initial velocity plus the product of acceleration and time.
