To calculate velocity from the position-time equation x = a + b(t^2), where a = 8.5m and b = 2.5m/(s^2), one must differentiate the equation with respect to time. The derivative dx/dt yields the velocity function v(t). After differentiating, substituting t = 2s into the velocity function provides the specific velocity at that time. The discussion also briefly touches on differentiation concepts, indicating a broader interest in calculus applications. Understanding these principles is essential for solving similar physics problems effectively.