Answer
a). $\frac{7}{12} ft/sec$
b.) $ \frac{3}{2} ft/sec$
c.) $ \infty$
Work Step by Step
For a. plug in 7 feet to the given equation.
a.) $r= \frac{2 \times 7}{\sqrt {625 - 49}}= \frac{7}{12} ft/sec $
Plug in 15 feet for b
b.) $r=\frac{15\times 2}{\sqrt {625-225}} = \frac{3}{2}$
c.) $\lim\limits_{x \to 25^-} \frac{2x}{\sqrt {625- x^2}}=\infty $ Because numbers just under 25 are approaching $ \infty $
