posted by bob .
A 640-kg racing car completes one lap in 14.3 s around a circular track with a radius of 45.0 m. The car moves at constant speed.
(a) What is the acceleration of the car?
(b) What force must the track exert on the tires to produce this acceleration?
a = v^2/r where v = 2 pi r/14.3
F = m a = 640 a