Centripetal Force: Why Static Friction is Used in Bank Curve Problems

[oreo]

Why do we use coefficient of static friction instead of coefficient of kinetic friction in bank curve problems

 

[Bystander]

When the wheels start sliding sideways things start getting complicated, and very exciting. When the part of the wheel in contact with the paved surface/track is not moving relative to the track (static case), things are under control.

 

[oreo]

When the wheels start sliding sideways things start getting complicated, and very exciting. When the part of the wheel in contact with the paved surface/track is not moving relative to the track (static case), things are under control.[/QUOTE

 

[oreo]

Thanks for the clear answer.

 

[PJC01]

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Centripetal force is the force that keeps an object moving in a circular path. In bank curve problems, we often use static friction as it is the force that allows the object to maintain its circular motion. This is because static friction acts in the direction of the centripetal force, keeping the object from sliding off the curved surface.

The coefficient of static friction, denoted by μs, is used instead of the coefficient of kinetic friction, μk, because in bank curve problems, the object is not sliding but rather rolling without slipping. This means that the point of contact between the object and the surface is stationary, and static friction is the only force acting on the object in the direction of the centripetal force.

On the other hand, the coefficient of kinetic friction is used when the object is in motion and sliding on the surface. In this case, there are other forces, such as the normal force and the weight of the object, that are also acting on the object. Therefore, using the coefficient of static friction, which only considers the force of static friction, is more appropriate for bank curve problems.

In summary, static friction is used in bank curve problems because it is the force that allows the object to maintain its circular motion, and the coefficient of static friction is used instead of the coefficient of kinetic friction because the object is rolling without slipping rather than sliding on the surface.