Seema enjoys a roller coaster ride in Ferrari world by first going downwards and then upwards to…

Seema enjoys a roller coaster ride in Ferrari world by first going downwards and then upwards to the maximum height. The relation between the distance travelled (cm) with respect to the time taken to complete the side by Seema is given by the following equation: $y = 4x - \frac{1}{2}x^2$ where $x = \text{time in seconds}$.