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.