3. Analysts use the formula $v = f(L) = \sqrt{20L}$ to estimate the speed of a car, v, in miles per hour,
based on the length, L, in feet of its skid marks when suddenly braking on a dry, asphalt road.
However, they have found that the formula is only accurate for skid mark lengths between 20 and
320 feet long.
Find the inverse function $L = f^{-1}(v)$, and state its domain.
4. The formula $v = g(r) = \sqrt{2.6r}$ models the maximum safe speed, v, in miles per hour, at which a
car can travel on a curved road with radius of curvature r, in feet, where $80 \le r \le 960$ feet.
Find the inverse function $r = g^{-1}(v)$, and state its domain.
5. Create a function, using the above, that determines the stopping distance L, of a car traveling the
maximum safe speed on a road with radius of curvature r. State the domain and range of your
function.
