Centripetal force

1. Jul 27, 2009

dance_sg

1. The problem statement, all variables and given/known data
A 1.00 x10^3 kg car is moving through a flat curve on a road at a velocity of 30.0 m/s. If the coefficient of friction between the road and the tires is 0.600, the radius of the curve is

2. Relevant equations
r=v^2/(coefficitent of friction)(g), r=mv^2/F

3. The attempt at a solution
I tried two ways so solve this question, but im not sure which was is correct.
the first thing i did was, find F by multiplying 9.81m/s2 and the mass (1000). then plugging that into the r=v^2/f. Then i used the first formula i provided above and just plugged all the variables in (excluding mass). Does the mass need to somehow be in there?

2. Jul 27, 2009

diazona

In $r = mv^2/F$, the force should be the centripetal force that holds the car in the curve, not the weight of the car.

3. Jul 27, 2009

dance_sg

so 30^2 divided by 0.600 times 9.81m/s2 giving me 153m, would be the correct answer?

4. Jul 27, 2009

diazona

Yep, that's it. But you should make sure you get the same answer both ways.

5. Jul 27, 2009

dance_sg

Alrite. thank you =)