# Non uniform circular motion and friction

1. Oct 31, 2005

### newcool

What are the Forces of a car that is accelerating around a circle? There is friction between the road and the car.

Centripital force(in towards the circle)
Static Friction(in towards the circle)

However there is also another component of friction that I am missing?
Any ideas?

Thanks

2. Oct 31, 2005

### HallsofIvy

Staff Emeritus
If the car is going around in a circle, its tires are aimed tangent to the circle, not in or out. Isn't there friction between the tires and the road that is accelerating it?

3. Oct 31, 2005

### newcool

I thought that was the static friction.

4. Oct 31, 2005

### Tide

Halls didn't claim otherwise. He's telling you that the car is accelerating and suggesting to you what the accelerating force is.

5. Oct 31, 2005

### newcool

So There is friction perpendicular to the centripital force and friction parallel to centripital force. How are the 2 related?

6. Oct 31, 2005

### Tide

Friction provides the centripetal force. Otherwise, the car would travel off in a straight line. Your original question is sufficiently broad that you will have to include the force provided by the engine which acts through torque on the wheels and friction with the road.

Do you have a specific problem in mind?

7. Oct 31, 2005

### Tide

Is the acceleration uniform and are you given some rate of acceleration?

8. Oct 31, 2005

### newcool

No information about acceleration is given. Teacher said that when you draw the right FBD it will become very simple

9. Oct 31, 2005

### newcool

bump. Any help appreciated. Thanks

10. Oct 31, 2005

### Tide

Sorry - just got back. I have to think some more about that. I think something is missing.