Question

theme park ride is descending on a parabolic path that can be approximated by the equation… (distance measured in feet.) If the horizontal component of its velocity is a constant 9 ft/s, find the rate of change of its elevationhenr = 30.

Answer 1

`\begin{gathered} y=-(1)/(90)x^2+75 \\ \frac{dy}{\text{dt}}=-(1)/(90)(2x)(dx)/(dt) \\ \\ \end{gathered}`
`\begin{gathered} (dy)/(dt)=-(1)/(90)(2*30)(9) \\ \\ (dy)/(dt)=-(1)/(90)(60)(9) \\ \\ (dy)/(dt)=-(1)/(9)(6)(9) \\ \\ (dy)/(dt)=-(1)/(9)(54) \\ \\ (dy)/(dt)=-6\text{ ft/s} \end{gathered}`