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kashiark
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I was thinking about it, and the only thing I could come up with is that it reduces friction with the surface the object is sitting on and perhaps it distributes weight evenly?
kashiark said:I was thinking about it, and the only thing I could come up with is that it reduces friction with the surface the object is sitting on...
atyy said:But does rolling friction come into play in ideal rolling without slipping - in such a case the point of contact is always stationary?
atyy said:But does rolling friction come into play in ideal rolling without slipping - in such a case the point of contact is always stationary?
kashiark said:Why is rolling friction less? It seems like common sense that it is, but why is it?
The question was why rolling friction is less than sliding friction. The area of contact of a rolling wheel is the same, as if the wheel slides. It is not the size of the contact area, but it's movement relative to the ground: In the rolling case the area of contact has no horizontal speed.Pengwuino said:The area of contact at all times is extremely small for a very spherical object
Pengwuino said:The area of contact at all times is extremely small for a very spherical object
negitron said:You can immediately falsify this statement by asking yourself why brakes work, since the area of contact with the ground doesn't change, the wheels just stop turning.
negitron said:Rolling friction occurs even when the wheel doesn't slip. Friction, as a general case, occurs when electrostatic forces act between the surface atoms of one body moving over the surface atoms of another. Sliding is not the only case in which this occurs. For a wheel, there is always some portion of it in contact with the surface over which it rolls, and as it turns, atoms on the wheel's leading surface are continually being mashed down onto the surface of travel where electrostatic forces weakly bind them then are pulled apart again at the trailing surface--the energy required to pull those weak bonds apart is what we call friction.
kashiark said:I see what negitron is trying to say. If the wheels aren't turning, the friction increases regardless of the small contact area of the wheel touching the ground.
kashiark said:However, could changing the atoms which are reacting with the ground decrease friction? Or am I just wrong?
negitron said:Rolling friction occurs even when the wheel doesn't slip. Friction, as a general case, occurs when electrostatic forces act between the surface atoms of one body moving over the surface atoms of another. Sliding is not the only case in which this occurs. For a wheel, there is always some portion of it in contact with the surface over which it rolls, and as it turns, atoms on the wheel's leading surface are continually being mashed down onto the surface of travel where electrostatic forces weakly bind them then are pulled apart again at the trailing surface--the energy required to pull those weak bonds apart is what we call friction.
Wheels are designed to reduce the friction between an object and the surface it is moving on. This decreases the amount of force needed to move the object, thereby reducing the amount of energy required.
Wheels are round and have a small contact area with the surface, which means there is less overall surface area for friction to occur. Additionally, wheels are often made of materials that are smooth and slippery, further reducing friction.
Yes, most types of wheels are designed to decrease the amount of energy needed to move an object. However, the effectiveness of this reduction may vary depending on factors such as the weight of the object, the surface it is moving on, and the type of wheel being used.
Wheels are most effective on smooth and flat surfaces. Rough or uneven surfaces may cause more friction, making it more difficult to move an object even with wheels. In some cases, specialized wheels may be designed for use on specific surfaces, such as off-road wheels for bumpy terrain.
Wheels significantly increase the efficiency of moving an object by reducing the amount of energy needed. This is due to the reduced friction between the object and the surface. In some cases, wheels may also provide leverage, making it easier to move heavier objects with less effort.