Friction for different contacts

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The discussion centers on the differences between rolling friction and sliding friction, highlighting that rolling friction is less due to energy loss from deformation rather than traditional friction. It clarifies that the friction at the contact point of a rolling object is static friction, while sliding involves dynamic friction. Additionally, rolling resistance, often referred to as rolling friction, is a minor force resulting from deformation and can typically be disregarded in calculations. The conversation emphasizes the importance of understanding these distinctions for a clearer grasp of frictional forces. Overall, the nuances of friction types are essential for comprehending their effects in various contexts.
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Hi all,
I know this is a very basic question and has been discussed in various threads.Anyway i would i like to ask this.

If the value of friction only depends on coefficient of friction and normal force, why is rolling friction less than sliding friction? Is it because the value of Rn the reaction force changes?

I know this is very elementary but I thought it would make my understanding better.

Thanks in advance
 
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hi sriram123! :smile:
sriram123 said:
If the value of friction only depends on coefficient of friction and normal force, why is rolling friction less than sliding friction? Is it because the value of Rn the reaction force changes?

"rolling friction" isn't actually friction, it's a loss of energy caused by continual deformation of the wheel where it meets the surface :wink:

from the pf library:
Friction:

Friction at the point of contact of a rolling body is static friction.

There is also a rolling resistance, or "rolling friction": an additional small force, caused by deformation of the body (in exam questions it can usually be ignored).

Friction at the point of contact of a sliding body is of course dynamic friction.
 
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