What is Rolling: Definition and 1000 Discussions

Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact with each other without sliding.
Rolling where there is no sliding is referred to as pure rolling. By definition, there is no sliding when there is a frame of reference in which all points of contact on the rolling object have the same velocity as their counterparts on the surface on which the object rolls; in particular, for a frame of reference in which the rolling plane is at rest (see animation), the instantaneous velocity of all the points of contact (e.g., a generating line segment of a cylinder) of the rolling object is zero.
In practice, due to small deformations near the contact area, some sliding and energy dissipation occurs. Nevertheless, the resulting rolling resistance is much lower than sliding friction, and thus, rolling objects, typically require much less energy to be moved than sliding ones. As a result, such objects will more easily move, if they experience a force with a component along the surface, for instance gravity on a tilted surface, wind, pushing, pulling, or torque from an engine. Unlike cylindrical axially symmetric objects, the rolling motion of a cone is such that while rolling on a flat surface, its center of gravity performs a circular motion, rather than a linear motion. Rolling objects are not necessarily axially-symmetrical. Two well known non-axially-symmetrical rollers are the Reuleaux triangle and the Meissner bodies. The oloid and the sphericon are members of a special family of developable rollers that develop their entire surface when rolling down a flat plane. Objects with corners, such as dice, roll by successive rotations about the edge or corner which is in contact with the surface. The construction of a specific surface allows even a perfect square wheel to roll with its centroid at constant height above a reference plane.

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  1. Xiothus

    Solve First Year Harmonic Motion Problem: Cylinder Rolling

    Thank you guys for taking the time to read this - I'm decently struggling with first year and need some tips on how to properly conceptualize problems and learn what the right approach is on certain problems. Have a wonderful day, again thank you for checking this post out!
  2. uSee2

    Kinetic Energy of a Cylinder Rolling Without Slipping

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  3. P

    I Rolling Motion direction of Velocity center of mass

    Hi I have come across something confusing in rolling motion. If an object moves with a positive V_cm meaning to the right its angular velocity will be clockwise or negative. The formula is V_cm=wR but for a positive V_cm you get a negative w as it moves clockwise if V_cm is to the right...
  4. brochesspro

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    Here is the problem statement along with the figure. Here, I take the right-ward and anti-clockwise directions to be positive. After the ball collides with the wall, its angular velocity remains the same and its velocity changes direction while remaining the same in magnitude. Using the...
  5. P

    Rolling coin with point mass

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  6. A

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    a=2/3*g*sin(25*(pi/180))=>a=2.8507 m/s^2 vf=vi+at=>vf=0+2.8507*1.50=>vf=4.2760 m/s So the translational motion of the cylinder is 4.2760 m/s. 4.2760=R*w w=134.04 rad/s PE=mgh=>PE=215*9.8*.108=>PE=227.56 J PE = KE at the end of the roll because of energy conservation. 227.56 =...
  7. J

    I Rolling ball, change of direction

    Say I have a magic way to exert lateral forces on a free-rolling ball on a plane, with no slipping. Say I apply a force for a given period from the South, the ball starts rolling to the North and attains a constant speed. Then I suddenly apply the same force for the same period but from the...
  8. C

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    For part (c) of this problem, My working is However, the tricky part is to find theta. I tried to draw the situation so that I could find theta: It appears that theta = 90 degrees. However, this does not seem to be correct. Does anybody please know how to correctly find theta in terms of...
  9. T

    Coefficient of rolling resistance

    Hi, What is the formula or methodology for finding the Crr? There are many of those tests done on the internet, but none state the procedure of calculation. I'm trying to find the correlation between tire pressure and distance and want to use Crr as one of the key factors influencing it. Maybe...
  10. theshape89

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    Let ##R=\sqrt{x^{2} + y^{2}}##. Then \begin{align}v_{tangential}&=\frac{dR}{dt} \nonumber\\ &=\frac{dR}{dx}\frac{dy}{dt} + \frac{dR}{dy}\frac{dy}{dt} \nonumber\\ &=\frac{x}{R}\frac{dx}{dt} + \frac{y}{R}\frac{dy}{dt} \nonumber\\ &= cos\phi \frac{dx}{dt} + sin\phi \frac{dy}{dt}.\nonumber...
  11. P

    Rolling mill force calculations

    Hi, I'm building a rolling mill for flattening out bits of steel and I'm trying to make sure it's not going to break. I know that with a 1500w motor geared down to 60rpm (2pi rad/s) i end up with 239Nm of torque. 239Nm working at a radius of 0.0375m gives 6369N of force generated at the edge...
  12. tbn032

    B Why is static friction necessary for pure rolling?

    Suppose a cylinder is launched on a horizontal frictional surface such that it has initial translational velocity v and zero angular velocity .the kinetic friction would be applied between the contact points of the cylinder and the surface, opposite to the direction of the translational motion...
  13. tbn032

    B Rolling of non-deforming sphere on a non-deforming rough surface?

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  14. Harikesh_33

    Question regarding Rolling with and without Slipping and Sliding

    1)When a wheel is stuck in mud it rolls with slipping ,this means that at the point of contact it has a net velocity As we can see from the image Kinetic Friction acts in the direction opposite to the resultant velocity ,this effectively reduces the tangential velocity at the surface and tries...
  15. tbn032

    B Trouble understanding what rolling friction is

    In pure rolling the of the sphere contact points of the sphere are at zero velocity,how is friction opposite to the motion of sphere being applied to these points?how the frictional force f is bieng applied to the sphere?
  16. tbn032

    B Friction on pure rolling non deforming sphere?

    How will the friction work on a sphere which is purely rolling on a horizontal surface such that both the sphere and surface does not deform. The sphere at any time t will only have one point of contact, which would continuously changing as the sphere rolls. Will The friction be applied to the...
  17. pixel

    I Friction in rolling without slipping

    Consider an object, say a ball, rolling at a constant speed without slipping to the right on a horizontal surface. Let's consider the ideal case, so no deformation of ball or surface. For rolling without slipping to occur, there has to be friction (static friction as the point on the ball that...
  18. S

    Acceleration of system related to rolling motion and pulley

    There is no friction mentioned by the question so I assume the plane is frictionless but can the sphere roll without slipping if there is no friction? This is my attempt: Equation of translation motion of object A (assuming A moves upwards): TA - WA sin θ = mA . aCOM (A) TA = mA . aCOM (A) + WA...
  19. S

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    A force is given to the center of the object so the object rolls to the right without slipping. I understand that to provide clockwise rotation the static force should be directed to the left. But if the force F is located at the very top of the object, the static friction is directed to the...
  20. kuruman

    B Rolling motion test

    I am posting this to generate a parallel discussion to this ongoing thread. It seems that some participants in that thread have doubts and confusion about rolling motion that might be better addressed separately from the homework problem in question. It is a simple test of one's understanding...
  21. C

    I Friction of a rolling cylinder on an incline

    Hello everyone! I'm watching this Walter Lewin lecture and am at 5:58 part of the video I'm wondering how there's a frictional torque applied to the cylinder, my reasoning is that the object has forward velocity, and on a perfect cylinder, the slope of the incline touches the cylinder at a...
  22. V

    Rolling problem with friction

    This is a problem that was posted here in 2003 and is now closed for replies. This question can be found at https://www.physicsforums.com/threads/friction-problem.662/ The answer in that old post didn't seem clear to me probably because it was highly summarized. There was no mention of static...
  23. Sagittarius A-Star

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    Source: https://www.ema.europa.eu/en/news/ema-starts-rolling-review-covid-19-vaccine-hipra-phh-1v See also: https://clinicaltrials.gov/ct2/show/NCT05246137 Source: https://pharmaboardroom.com/interviews/carles-fabrega-managing-director-human-health-hipra/
  24. LCSphysicist

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  25. A

    B Rolling without slipping in non-sloping surface

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  26. Eobardrush

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  27. S

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  28. L

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  29. rebbe90

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  30. M

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  31. Hendra

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    Hello everyone! I tried to solve this problem in a non-inertial system. Probably I should use the principle of conservation of mechanical energy in the following form $$mgH = \frac{3mgR}{2} + \frac{mV^2}{2}.$$ So the only thing to do is to compute $V^2$. I tried to find this value using the...
  32. Einstein44

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    I was looking for a way to calculate the friction arising from the axle and wheel of a standard lab cart. I came across this research paper: https://www.usna.edu/Users/physics/mungan/_files/documents/Publications/PhysEd4.pdf That derived the following equation for the coefficient of rolling...
  33. GottfriedLenz

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  34. J

    I Gravitational Illusions -- Two balls rolling down differently-shaped ramps

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  35. T

    A Cylinder Rolling in a V-Groove

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  36. Ineedhelpwithphysics

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  37. Huzaifa

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  38. R

    I Rolling balls with different rotational inertia

    I am stuck on problem presented about putting golf balls. A stationary golf ball (mass=45g, dia=42mm, solid & homogeneous) is struck by a horizontal force (putter) and ignoring sliding immediately starts rolling on a level putting green. The ball eventually stops due to rolling resistance...
  39. M

    Expected value of median of rolling three fair dice

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  40. LCSphysicist

    Motion of Rolling Cylinder in Fixed Cylinder: Confusing Constraint Condition

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  41. T

    Automotive Speed of a car rolling down a hill

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  42. P

    Derive the period of a Ball rolling in a Bowl

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  43. A

    MHB Probability of Rolling Sum > 3 with Two Dice

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  44. Y

    Rolling pendulum angular acceleration

  45. Pipsqueakalchemist

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  46. J

    Automotive Rolling resistance coefficient on sand

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  47. dahoom102

    Direction of friction in a yoyo rolling on an inclined plane

  48. P

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    My question is this: - Friction exists (for no slipping/pure rolling to occur) - Why is the work done against friction not accounted for in the conservation of energy equation? Thank you!
  49. Hamiltonian

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  50. chucho11028

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    Hello This is not a homework, this is my own experiment to understand how the motion works. Please, follow my question here below: I have a hot wheels race with a slope with 10 degrees where I use a small car which departs from the top to the bottom. I have taken 5 times the time to get an...