Answer
1701 ft
Work Step by Step
1. Since there are 5280 ft in one mile and 3600 s in one hour we convert as
$v=70mph = \frac{70 mph}{1hr}\times\frac{1hr}{3600s}\times 5280 = 102.67 ft/s$
2. $R=\frac{v^{2}}{g(f + tan\theta)}$
$\theta=3^{\circ}$; $g = 32.2$ and $ f= 0.14$
$R=\frac{v^{2}}{g(f + tan\theta)}= \frac{102.67^{2}}{32.2(0.14 + tan 3^{\circ})}= 1701 ft$