Rolling Friction: Static, Kinetic, or Rolling?

[sArGe99]

When an object is said to be under pure rolling, what friction does it experience? Static, kinetic or rolling friction?
If its not rolling but rather just rotating and translating, what friction does it experience?

If a rolling body is kept on a surface of certain friction constant, does the friction force on it vary with changing angular velocity? Is the friction force still given by f = k * Normal reaction, which in the case mentioned is mg?

I appreciate any help.

 

[kuruman]

When an object is said to be under pure rolling, what friction does it experience? Static, kinetic or rolling friction?

If by "pure rolling" you mean "rolling without slipping", then it is static friction. I am not sure what "rolling friction" is.

If its not rolling but rather just rotating and translating, what friction does it experience?

Kinetic friction if it rolls with slipping (like a car "laying on the rubber" as it starts moving).

If a rolling body is kept on a surface of certain friction constant, does the friction force on it vary with changing angular velocity?

Yes if it rolls without slipping. The force of static friction will be whatever is necessary to provide the observed linear and angular acceleration.

Is the friction force still given by f = k * Normal reaction, which in the case mentioned is mg?

Yes but only if there is rolling with slipping, i.e. if the instantaneous point of contact on the rolling object is not at rest with respect to the surface on which it rolls.

I appreciate any help.

Good luck.

 

[kerimek]

Rolling friction is a type of friction that occurs when an object is rolling on a surface. It is a combination of both static and kinetic friction. When an object is under pure rolling, it experiences a combination of both static and kinetic friction. This is because the point of contact between the object and the surface is stationary, but there is also movement between the two surfaces.

If an object is just rotating and translating, it experiences a combination of kinetic and rolling friction. This is because there is movement between the object and the surface, but the point of contact is also moving.

When a rolling body is kept on a surface with constant friction, the friction force on it does not vary with changing angular velocity. This is because the friction force is still given by the equation f = k * Normal reaction, where k is the coefficient of friction and the normal reaction is equal to the weight of the object (mg in this case). This means that the friction force remains constant regardless of the object's angular velocity.