Rolling motion

[drragonx]

How does friction affect the type of rolling motion of an object. For instance, does having more friction than the required friction for rolling cause the object to spin?

 

[jerromyjon]

Friction is the resistance to motion. Force is required to overcome resistance then acceleration occurs and friction increases.

 

[drragonx]

Friction is the resistance to motion. Force is required to overcome resistance then acceleration occurs and friction increases.

I think you misunderstood me. A typical example is a ball rolling down an igloo from the top. The friction changes as it goes along the surface. So, when the ball starts sliding, is the friction less than or greater than required friction for rolling?

 

[jerromyjon]

Now I think I understand your question... the line between rolling and sliding, would vary greatly depending I think mostly on the mass of the ball then on the rolling resistance versus the sliding resistance which would be less to slide or more to roll. Similar to a car skidding on ice, braking increases rolling resistance.

 

[drragonx]

Correct me if i am wrong: The ball would spin (rotational>linear) if friction>required OR slid (linear>rotational) if friction<required. Finally, the ball would pure roll (vcm=rw) if friction=required.

 

[jerromyjon]

It would be a razor sharp line where rolling friction = sliding friction... it is a dynamic situation, any way I think about it there is not a way to maintain a balance there. Even if the ball starts on a surface where these frictions are balanced, sliding would cause some rolling or rolling would cause some sliding. No matter what the ball is going down its just which ever the least resistive way to get there is.