WHAT IS ROLLING FRICTION? // Rolling Resistance Explained // Example Problem and Equations Included!

In this video I explain what rolling friction, aka rolling resistance, and how it is used in engineering. I briefly explain where the equation for rolling friction comes from and then I go through an example problem involving rolling friction.
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[@ptiwaridotin]

Kudos to the presenter for this video, I would have preferred keeping the force in a unit of force like Newton rather than a unit of mass like the pounds. Mass & Weight are different just like Pounds and Newtons.

[@studentengineering]

Thanks! Pounds is the unit of force in English units and slugs is the unit of mass in English units. There is such thing as a pound mass but it is not the standard unit of mass in the English system.

[@soyalkhatri6464]

Nice info

[@studentengineering]

Thanks!

[@sebastianriveradominguez2301]

Good explained

[@studentengineering]

Thanks

[@ramangahlaut9850]

Hello dear. Can u tell me about the rail problem. When all boggies are connected in a sequence. 8 wheel each boggies. What will be required pull .

[@studentengineering]

What is a boggie?

[@ramangahlaut9850]

@@studentengineering train coach

[@studentengineering]

I need more information than that. Watch the video and find all the variables that are needed to solve the problem.

[@whoankur]

While calculating Moment at A, u forgot to consider force applied my the man

[@studentengineering]

The reason why I didn’t include the force P applied by the man is because when I summed moments about A I was solving for the normal force in each of the tires. Once we have those normal forces in the tires then we can solve for the rolling resistance. The sum of all those rolling resistance forces equals P. The force P doesn’t influence the normal force in the tires so we don’t need to include it in that summation of moments. Does that make sense?

[@bekhruznuraliev4431]

It is very helpful, thank you for that. However, I have a question: what if all the conditions are the same as in the video, but this time car itself is accelerating?

[@studentengineering]

If that was the case it would no longer be a statics problem but rather a dynamics problem. You would still need to solve for this same rolling resistance/force and then probably use it in the equation Force=mass*acceleration and then you could solve for whatever the dynamics problem asked for. This example problem just asked to find the force needed to just barely overcome the rolling friction and move the car at a constant speed. That means that the force to push the car and the rolling friction are the same.
Does that help?

[@bekhruznuraliev4431]

@@studentengineering thanks for response)), sure it does.

[@gameon8999]

Hi is rolling friction the only friction which should be considered when calculating force required to start a motion of a car,lets say this car has two driving whrels are two driven wheels at front.If other fricions between parts and viscous friction neglected,can I consider in order to start a motion traction force from drive wheels should only overcome rolling friction in driven wheels?thanks

[@studentengineering]

If I understand correctly what you are saying, the driving wheels would have to overcome both the rolling friction of the driving wheels as well as the rolling friction of the rear wheels. In other words, the rolling friction of all of the wheels would have to be overcome to get the car in motion.

[@gameon8999]

@@studentengineering thanks for the quick reply,I have a doubt on what is the minimum required force to start moving a car with two drive and two driven wheels, does required force has any effect from static friction between wheels and ground,or is it all depends on rolling friction? Thanks

[@apeayeigbeneghu]

Does kinetic of rolling friction have dimension 😢

[@studentengineering]

Great question! We assume the wheel doesn’t slip with relation to the ground so there isn’t any kinetic friction.

[@jeraldobasha]

This video/channel deserves better

[@studentengineering]

Thanks!

[@shikhasoni2329]

Hi sir

[@studentengineering]

Hello

[@shikhasoni2329]

where are you from

[@studentengineering]

USA

[@mahdihosseini6361]

beside all that stuff you have a very sexy voice ngl

[@studentengineering]

Haha thanks

[@calholli]

So roughly 3%..
Why didn't you just say so. :)

[@studentengineering]

Haha yep :)