Friction on on circular objects while rolling?

[prashantjha]

friction on on circular objects while rolling??

i had a doubt about circular rolling objects..
it is true that friction opposes relative motion..but while doing so in a rolling wheel rolling forward,the friction also works in forward direction.so then my question is why does the wheel stops after a particular time.if friction is helping it move,then it should move till infinity if left undisturbed??

 

[Bloodthunder]

friction is not helping it move, friction is helping it roll. without friction, the ball is unable to roll at all and will just slip down the slope.

also, the friction on the ball is not in the direction of movement but in the opposite direction, it is the friction on the ramp by the ball that is in the ball's direction of movement. so the friction on the ball is still going in the opposite direction and eventually stops the ball.

 

[mikeph]

Friction is not helping it roll in any sense. If you magically removed friction halfway through the experiment, conservation of angular and linear momentum would mean the ball continues in exactly the same way as before (with the exception that it never slows down).

Friction initially influences the rolling motion by enforcing the non-slip condition v = rw. After this, it doesn't do anything but slow the ball down.

 

[rcgldr]

i had a doubt about circular rolling objects..
it is true that friction opposes relative motion

Rolling resistance opposes relative motion. This is due to the losses in deformation (compression) and restoration (expansion back to original shape) of the surfaces at and near the contact point.

Static friction opposes external forces.

Kinetic (sliding) friction opposes relative motion between surfaces, but in this case, an object is not truly rolling any more.

 

[PJC01]

Friction is a force that opposes the relative motion between two surfaces in contact. In the case of circular objects rolling, there are two types of friction at play: static friction and kinetic friction.

Static friction occurs when the object is at rest and prevents it from moving. When a circular object is rolling, static friction acts in the opposite direction of the motion, providing the necessary force to keep the object rolling.

However, as the object continues to roll, kinetic friction comes into play. Kinetic friction is the force that opposes the motion of an object that is already in motion. This force acts in the same direction as the motion, but it is smaller than static friction.

As the object continues to roll, the force of kinetic friction gradually increases, eventually becoming equal to the force of static friction. At this point, the object will stop rolling as there is no longer a net force acting on it.

Additionally, other factors such as air resistance and imperfections in the surface can also contribute to the eventual stopping of the rolling object.

In summary, while friction does play a role in keeping a circular object rolling, it is not the only force at play and there are other factors that contribute to the eventual stopping of the object.