The van travels over the hill described by $\displaystyle y = (-0.0015x^2 + 15) ft.$ If it has a constant speed of $\displaystyle 75 ft/s,$ determine the x and y components of the van's velocity and acceleration when $\displaystyle x = 50 ft.$

This is what I found:

$\displaystyle v_y = -0.15v_x$

$\displaystyle v = \sqrt{v_x^2 + v_y^2}$

$\displaystyle v_x = 74.17 ft/s \leftarrow$

$\displaystyle v_y = 11.13 ft/s \uparrow$

$\displaystyle a_y = -16.504 - 0.15a_x$

Now, how to complete the answer?