physics help?

[First L]

You want to test the grip of the tires on your new race car. You decide to take the race car to a small test track to experimentally determine the coefficient of friction. The racetrack consists of a flat, circular road with a radius of 45m. The applet shows the result of driving the car around the track at various speeds.What is the coefficient of static friction between the tires and the track?
the applet can be found here
http://media.pearsoncmg.com/bc/aw_young_physics_11/pt1a/Media/CircularMotion/CarCirclesTrack/Sim3.html

[Paul B]

Find the maximum speed at which the car will hold the track.

At this speed, centripetal force = maximum frictional force

mv^2/r = mg*(coeff.friction)

Make coeff. friction the subject of the eqn, insert values, and solve.

The Q is quite right to say "coeff static friction", even though the car is moving. Why?