Rolling Friction Examples
Laws of Rolling Friction
Rolling Friction Equation
Rolling Without Slipping
Advantages of Rolling Friction
When a soccer ball is kicked, it stops after rolling on the ground.When a golf ball is hit, it stops on the green after rolling.A car will come to a stop after rolling downhill and reaching a flat road.A skateboard moving on wheels will come to a stop after some time.A roller coaster slows down its ride towards the end due to a flat strip of track.
Directly proportional to the normal loadInversely proportional to the radius of curvatureDecreases as the surface roughness is reduced, i.e., less for smoother surfaces
FL = mg Also, from laws of friction, the rolling frictional force FR is proportional to the normal load. FR ∝ FL Or, FR = μR FL Or, FR = μR mg The constant of proportionality is called the coefficient of rolling friction. It takes a constant value depending on the nature and material of the surfaces. It is unitless and dimensionless, whereas the unit of rolling friction is Newton or N. For example, the coefficient of rolling friction between the tire and road is 0.7 for dry road and 0.4 for the wet road. v = wR a = ∝R Where, v is the translational velocity, w is the angular velocity, a is the translational acceleration, ∝ is the angular acceleration, and R is the radius of the object. The rolling friction force prevents the object from slipping. Its direction is the same as that of the translational velocity. If the object rotates clockwise on a flat surface, the friction will be directed towards the right. Similarly, if the object is rolling up a hill, the friction will be directed upwards. Also, since the point of contact is stationary, the work done by friction in pure rolling is zero.
Reduces the friction between an object and a surface, i.e., lower than sliding frictionAllows an object to move smoothly over a surfaceAllows an object to roll up a hillLuggage fitted with wheels roll easily
