# Bicycle Race

1. Nov 8, 2006

"A cyclist competes in a one-lap race around a flat, circular course of radius r . Starting from rest and speeding up at a constant rate throughout the race, the cyclist covers the entire course in a time t. The mass of the bicycle (including the rider) is m. What is the magnitude of the net force acting on the bicycle as it crosses the finish line?

Find F(net), the magnitude of the net force acting on the cyclist at the finish line.

Express the net force in terms of r, t,m , and pi."

First I tried to break it down into components.

F(net) = sqrt (net tangential force^2 + net radial force^2)

net tangential force = (m4pi*r)/t^2

I know that I will need to use Newton's 2nd law to find the tangential force. But I can't figure out how to do this.

As for the net radial force I know that I somehow need to use tangential force but since I'm stuck there that's as far as I got.

Thanks.

2. Nov 8, 2006

### Staff: Mentor

Do it step by step:
- What's the tangential acceleration? (You found it already.)
- What's the radial acceleration? (Hint: What's the speed as he passes the finish line?
- What's the total acceleration?