Can Friction Be Zero for a Rolling Sphere on a Surface?

Click For Summary

Homework Help Overview

The discussion revolves around the conditions under which a spherical body rolling on a rough surface may experience zero frictional force. Participants explore the implications of the statement that "the frictional force may or may not be zero," particularly in the context of rolling without slipping and the nature of the surface involved.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants question the conditions that would lead to zero friction, such as the presence of net external forces or torques. Some discuss the implications of a rough surface and the concept of pure rolling versus slipping.

Discussion Status

The discussion is active, with participants sharing differing viewpoints on whether friction is necessary for rolling. Some have provided insights into the mechanics of rolling motion, while others seek clarification on specific terms and conditions, such as the definition of a rough surface and the effects of changing surface conditions.

Contextual Notes

There is an emphasis on the definitions and assumptions regarding the surface and the rolling motion, including the distinction between rolling without slipping and the potential for slipping if the surface becomes smooth.

a.ratnaparkhi
Messages
30
Reaction score
0

Homework Statement


A spherical body is rolling on a rough surface.
then "the frictional force may or may not be zero"
Is this statement is correct or not?
we discussed about this in classroom.
Some were saying it must not be zero and others were saying it may be zero.
Which is correct?
 
Physics news on Phys.org
a.ratnaparkhi said:

Homework Statement


A spherical body is rolling on a rough surface.
then "the frictional force may or may not be zero"
Is this statement is correct or not?
How can it not be, since it covers all bases. :smile:
we discussed about this in classroom.
Some were saying it must not be zero and others were saying it may be zero.
Which is correct?
Depends. Is it rolling without slipping? Is the surface horizontal?
 
Doc Al said:
How can it not be, since it covers all bases.

What do you mean by this line. I did not get you.
 
a.ratnaparkhi said:

A spherical body is rolling on a rough surface.
then "the frictional force may or may not be zero"



Is any net external force or net torque (without considering friction) acting on the body?
If not then no friction force is acting. this is because:
Since it is purely rolling the point of contact has zero velocity with respect to the surface and also there is no acceleration of any form which has to be canceled by friction.

when there is any net force or torque friction tries to oppose it eg sphere rolling down an incline. but here there is no such problem
 
define a "rough surface" and it's interaction with the rolling body.
 
here rolling and rough surface imply that pure rolling is taking place (without slipping) and the surface is capable of providing friction. Suppose this question is asked to you in an exam would ask such a question.
 
Yes the surface is horizontal.Now, my opinion is if the surface suddenly becomes smooth then this body will start slipping i.e pure translational motion will start.
So, Without friction, it will not roll.
am I correct?
 
a.ratnaparkhi said:
Now, my opinion is if the surface suddenly becomes smooth then this body will start slipping i.e pure translational motion will start.
So, Without friction, it will not roll.
am I correct?
If it's already rolling, what will change that if there's no friction?
 

Similar threads

Friction Required for Billiard Ball to Roll without Slipping
  • · Replies 60 ·
3
Replies
60
Views
5K
Motion of Sphere Rolling Down Rotating Cone
  • · Replies 9 ·
Replies
9
Views
2K
Static equilibrium | Uniform sphere on incline | Determining friction
  • · Replies 43 ·
2
Replies
43
Views
3K
Another rotation problem -- Acceleration of a ring rolling on a surface
  • · Replies 1 ·
Replies
1
Views
908
Why is the direction of kinetic/static friction up a ramp?
  • · Replies 7 ·
Replies
7
Views
2K
How can we model a rolling truck on an incline using rotational motion analysis?
  • · Replies 24 ·
Replies
24
Views
3K
Acceleration of system related to rolling motion and pulley
  • · Replies 35 ·
2
Replies
35
Views
5K
Wooden sphere rolling on a double metal track
  • · Replies 97 ·
4
Replies
97
Views
6K
Rod with Current on Rails in Magnetic Field
  • · Replies 12 ·
Replies
12
Views
2K
Ring and solid sphere rolling down an incline - rotation problem
  • · Replies 8 ·
Replies
8
Views
4K