A person tosses a ball across a field. The trajectory of the ball is given by the following formula:

$$y = - 2.5 \space x^2 + 16 \space x + 1.8$$

The $x$-component of the ball's velocity at $x = 4.1 \space m$ is $v_x = 1.1 \space m/s$. What is the $y$-component of the ball's velocity at this position?