No, that's not right.

Try it again.

And be careful with the units!

Try changing everything to SI units;

find v_i = 70 mi/hr in units of m/s

and x - x_i = 186 feet in units of meters.

Anyway, 9.8 m/s² is "g", the acceleration due to gravity.

a = - g = - 9.8 m/s² might show up in a free fall problem but

it would be an unlikely coincident for that number to show up here.

(c) 2001, Doug Davis; all rights reserved.