2
$\begingroup$

According to Wikipedia, "Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface."

But at the same time, it is the static friction that is responsible for the forward movement of the wheels of a vehicle, according to many sources. But by the above definition, should it not be the rolling friction that comes into play?

I had also found rolling friction to be defined as follows: "Rolling resistance tends to be a catch all term for the energy dissipated in the many moving parts as a vehicle moves."

(For more, please visit Rolling resistance and static friction )

1) So, which definition is the right one?

2) Also, which friction is applicable for the motion of the wheels of a vehicle?

3) The motion of the wheels of a vehicle is considered "rolling without slipping". I know this sounds stupid, but does the condition "rolling and slipping" exist?

$\endgroup$
1
$\begingroup$

Static friction is what keeps the object rolling (where molecules of the object and the surface essentially act like cogs in a wheel).

Rolling friction refers to the processes of rolling that cause kinetic energy to be turned into heat (which by definition can't be static friction). For example, a rolling basketball becomes slightly deformed (the part touching the ground is smushed in/not perfectly spherical) as it rolls - more so the less it's inflated. That deformation absorbs kinetic energy as heat.

If you have an axle in a car, then you can lump the friction of the axle into rolling friction since it's not a scientifically rigorous definition.

For rolling and slipping, imagine tires on ice. Slipping leads to kinetic (and not just static) friction.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.