# Banking curve problem (find maximum speed)

1. Mar 2, 2013

### 5ymmetrica1

1. The problem statement, all variables and given/known data
A car travels around a circular curve on a flat, horizontal road at a radius of 42meters.
the maximum frictional force between the tyres and the road is equal to 20% of the weight of the car
calculate the maximum speed at which the car can travel around the curve at a constant radius of 42 meters

2. Relevant equations
I think Im supposed to use v = √rg
But I don't have a set of answers for these problems so Im not sure as this doesn't include the part of the question, the maximum frictional force between the tyres and the road is equal to 20% of the weight of the car

3. The attempt at a solution

v = √42*9.8
∴ v = 20.29 m/s

2. Mar 2, 2013

### rude man

The centripetal force is mv^2/R but what force is in play to produce that force ? It's not mg since that's the weight of the entire vehicle. What's the static friction force?

3. Mar 2, 2013

### 5ymmetrica1

I haven't studied any formula for static friction at this time in my physics course so I'm not quite sure what you mean sorry.

I know Fw = Fg (and Fv is equal but opposite in direction)

and that when split into vector components Fh = Fc

so is the frictional force Ff = FN (Normal force)?

4. Mar 3, 2013

### lep11

You don't need the actual formula of friction since you know Fμ=0.2*G

5. Mar 3, 2013

### rude man

If yo have a weight W sitting on the table and the coefficient of static friction is μ, how much horizontal force can you apply before it starts to slip?