4) A drag racer starts from rest and accelerates at 10 m/s2 for the entire distance of 400 m (1/4

mile). What is the velocity of the race car at the end of the run?

Start with the givens and the unknown:

vi = 0

a = 10

d = 400

vf = ?

The kinematics equation incorporating these variables is:

vf^2 = vi^2 + 2ad

vf^2 = 0 + 2 (10) (400)

vf^2 = 8000

vf = 89.4 m/s