Chapter R.4, Problem 82E

Stopping distance on glare ice. The stopping distance (at some fixed speed) of regular tires on glare ice is a linear function of the air temperature F,

$D\left(F\right)=2F+115,$

(a) $D\left(0°\right)=115\text{ft},D\left(-20°\right)=75\text{ft},D\left(10°\right)=135\text{ft},D\left(32°\right)=179\text{ft}$

where $D\left(F\right)$ is the stopping distance, in feet when the air temperature is F, in degrees Fahrenheit.

a. Find $D\left(0°\right),D\left(-20°\right),D\left(10°\right)$ and $D\left(32°\right)$.

b. Explain why the domain should be restricted to the interval $\left[-57.5°,32°\right]$.