# Speed of a bicycle - circles

1. Mar 8, 2006

### sauri

Suppose you ride a bicycle on a horizontal surface in a circle with a radius of 20 m. The resultant force exerted by the road on the bicycle (normal force plus frictional force) makes an angle of 15 degs with the vertical.
a. What is your speed?
b. If the frictional force is half its maximum value, what is the coefficient of static friction?

The problem is I got 2 equations that i can think of to solve for a). One equation is a=V^2/r and the other is F=mrw^2. But for the second equation I don't know the w(angular vel) and for the first I don't know a(acceleration). So how do I solve this?

2. Mar 8, 2006

### tony873004

Your rotational force is
$$\frac{Mv^2}{r}$$
Can you use this to find an expression for your frictional force? (hint: no math needed)