If you are traveling 25 m/s A) What acceleration is necessary to stop you in 40 meters? B) What force would stop you if you are driving a 2000 kg car? C) What is the coefficient of friction between your tires and the road?

A. V^2 = Vo^2 + 2a*d.

0 = 25^2 + 2a*40
a = ?(It will be negative).

B. F = M*a(F will be negative).

C. Fn = M*g = 2000 * 9.8 = 19,600 N. = Normal force.
Fk = u*Fn = 19,600u = Force of kinetic friction.

F-19,600u = M*a.
F = Value calculated in part B.
a = Value calculated in part A.
u = ?