Lectures on Physics has been derived from Benjamin Crowell's Light and Matter series of free introductory textbooks on physics. See the editorial for more information....

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).

Last Update: 2009-06-21