Can Static Friction Exist on a Moving Bicycle on a Flat Track?

AI Thread Summary
Static friction can exist on a moving bicycle due to the instantaneous rest of the contact point between the tires and the track. The discussion centers on calculating the smallest radius of an unbanked track for a bicyclist traveling at 29 km/h, given a coefficient of static friction of 0.29. The relationship between static friction and the normal force is crucial, as the maximum static friction helps maintain circular motion. The equations provided link the forces acting on the bicycle to its speed and radius of the track. Understanding that static friction applies at the contact point clarifies the dynamics involved in the scenario.
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Homework Statement



What is the smallest radius of an unbanked (flat) track around which a bicyclist can travel if her speed is 29 km/h and the coefficient of static friction between tires and track is 0.29?



Homework Equations



coefficient of static friction = (f of maximum static friction / Normal force)

fnet = ma = m * v^2 / r

The Attempt at a Solution



If an object is moving, isn't their just kinetic friction? I get that the normal force is the acceleration, but how can there possibly be a maximum static friction at this point?

Here's what I've got:

29km/h = 8.0556 m/s

.29 = fstatmax / a, therefore a = fstatmax / .29

Fnet = m* a = m * (v^2 / r)
Fnet = a = v^2 / r
fstatmax / .29 = (8.0556)^2 / r

Thanks for any help!
 
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If an object is moving, isn't their just kinetic friction?

In case of tyres, the bottom-most point is instantaneously at rest. That's why static friction.

f=0.29Xmg.
f=\frac{m{v^2}}{r}

solve to get r.
 
Ah...
thank you for the help!
 
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