The problem presented involves determining the maximum safe speed at which a sports car can travel along an inclined curve without slipping. Here is a step-by-step breakdown of how to approach this problem:

Given Data

• Inclination of the road ($\theta$): $30^\circ$
• Radius of curvature ($\rho$): $500$ feet
• Coefficient of static friction ($\mu_s$): $0.2$

Objective

Determine the maximum safe speed ($v_{\text{max}}$) so that the car does not slide.

Approach

To solve this problem, we need to analyze the forces acting on the car as it moves along the inclined curved path. The car experiences:

1. Gravitational Force ($mg$) directed vertically downwards.
2. Normal Force ($N$) perpendicular to the inclined surface.
3. Frictional Force ($f$) that acts to prevent slipping, directed up the incline.

For the car to avoid sliding, the centripetal force required for the turn must not exceed the maximum frictional force available.

Step-by-Step Solution

1. Resolve forces along the incline:

   • The gravitational component perpendicular to the incline: $mg \cos \theta$.
   • The gravitational component parallel to the incline: $mg \sin \theta$.

2. Normal Force ($N$): Since there is no vertical acceleration along the incline, $N = mg \cos \theta$

3. Frictional Force ($f$): The maximum static friction force is given by: $f = \mu_s N = \mu_s mg \cos \theta$

4. Centripetal Force Requirement: The centripetal force required to keep the car moving in a circular path of radius $\rho$ at speed $v$ is: $F_c = \frac{mv^2}{\rho}$

5. Balance of Forces for Maximum Speed: To prevent slipping, the frictional force must provide the necessary centripetal force. Thus, $\mu_s mg \cos \theta + mg \sin \theta = \frac{mv^2}{\rho}$

6. Solve for $v$: Substitute the given values and solve for $v$: $v^2 = \rho (\mu_s g \cos \theta + g \sin \theta)$ $v = \sqrt{\rho (\mu_s g \cos \theta + g \sin \theta)}$

7. Insert Numerical Values:

   • $\mu_s = 0.2$
   • $g = 32.2 \, \text{ft/s}^2$
   • $\theta = 30^\circ$
   • $\rho = 500 \, \text{feet}$ $v = \sqrt{500 \times (0.2 \times 32.2 \times \cos 30^\circ + 32.2 \times \sin 30^\circ)}$

Calculate each component to find the maximum speed $v_{\text{max}}$.

Would you like me to complete the calculation, or do you have any questions about the steps so far?

Further Questions:

1. What if the coefficient of friction was higher, such as 0.4? How would that impact the maximum speed?
2. How would the solution change if the incline angle was different, say $45^\circ$?
3. How does this calculation relate to real-world driving safety on curves?
4. What role does the radius of curvature play in determining safe driving speeds on curves?
5. How does static friction differ from kinetic friction in this scenario?

Tip

Remember that frictional force acts to prevent relative motion between surfaces, which in this case, helps the car to "stick" to the inclined curve.