# A little confused

1. Sep 18, 2006

### Fittler

A little confused....

:grumpy: Allright, I am doing Grade 12 University Prep. Physics, and I am almost finished the 4th Lesson. But I hit this one question and I am little stumped, my teacher does not com in for 15 minutes or so, so I thought maybe you guys would like to help me.

The initial scenario is this: A race car driver is driving her car at a record breaking speed of 225 km/h = 62.5m/s. The first turn on the course is banked at 15(deg), and the cars mass is 1450kg.

a) Calculate the radius of the curvature for this turn.

Which I did, no problem.

b) Calculate the centripetal acceleration of the car.

Again, no problem.

c) If the car maintains a circular track around the curve, what is the mganitude of the force of static friction?

So I calculated to force of static friction, which ended up being 0.27.

d) What is the coefficient of static friction necessary to ensure the safety of this turn?

Now I am stumped, didn't I just answer this question? Or rather how would I anser this question?

2. Sep 18, 2006

### Hawknc

The force of static friction is measured in Newtons, it's what acts on the car to keep it from sliding. The coefficient of static friction is a dimensionless number, usually less than 1. I can tell you right now that a car's friction force will be quite a bit greater than 0.27N...

3. Sep 18, 2006

### Fittler

Hahaha. You know what? I figured it out like right after I posted this. Thanks. Everything is fine now:)

4. Nov 15, 2006

### MattsVai

You figured it out eih? Well my friend this question if FLAWED. Yepp, it is MISSING DATA. There is no way you can determine r with the data given. So whatever u figured out, u figured out wrong :)