Force required to turn on a bike

A bicyclist is making a turn along an arc of a circle with radius 20 m, at a speed of 5 m/s. If the combined mass of the cyclist plus the bike is 60 kg, how great a static friction force must the road be able to exert on the tires?

Taking the magnitudes of both sides of Newton's second law gives

Substituting |a| = |v|²/r gives

(rounded off to one sig fig).