what is frictions?types of frictions?
153998
If you examined almost any surface under very high magnification, what looked smooth to the naked eye would look like endless mountain ranges in all directions.  If you then place two such surfaces together using weight or another force to join them and tried to move one surface relative to the other, the opposing "mountains" would have to slide up and over each other or even break (shear) the mountain tops.  The resulting resistance to motion is called friction.  When mountain tops are sheared, the energy forcing the motion is converted to extremely high local heat at the molecular level as bonds between millions of atoms and molecules are broken.  Friction causes heat and can quickly destroy an engine bearing that loses its lubrication.\n\nThe high heat of friction can actually cause a lubricant (oil, etc.) to break down and bond (as olifins) to the metal parts making smoother surfaces, especially when the parts are held apart by a film of circulation oil that carries away excess heat to a heat exchanger.  Grease (which is often a mixture of soap and oil) is thicker than oil and can fill the microscopic mountain valleys so that the parts slide on opposing layers of grease reducing friction and heat.\n\nWhen you push on a heavy crate, you must apply enough force to overcome the static friction (sometimes called stiction) and start the crate moving.  Continued motion creates dynamic friction generating a constant supply of heat.\n\nIf you place any object on a board and lift one end, all materials (combinations of board (incline) and object (load) will slide before the board reaches an angle of 45 degrees.  The higher the board angle, the higher the coeficient of friction.  This method can be used to calculate the coefficients of friction for various combinations of materials (board and load).  Ice on teflon has perhaps the least coefficient of friction and is very slippery.  The objects and board should not serve as cogs or act as adhesives to get valid results.\n\nFamily friction (strife) is the only kind of frictioon that can be reduced by flowers or a hug and a kiss.  That may cover most of the other types of friction, right?
27382
advantage:\n\nfriction, resistance offered to the movement of one body past another body with which it is in contact. In certain situations friction is desired. Without friction the wheels of a locomotive could not “grip” the rails nor could power be transmitted by belts. \n\ndisadvantage:\n\nOn the other hand, in the moving parts of machines a minimum of friction is desired; an excess of friction produces heat, which in turn causes expansion, the locking of the moving parts, and a consequent breakdown of the machinery. Lubrication is important in minimizing friction as are also such devices as ball and roller bearings.
32662
actually the limiting friction is greater than kinetic friction.  it takes more force to overcome the forces of the limiting friction(start the object moving) then it does to overcome kinetic friction(keep the object moving). this makes sense logically, once the object is sliding, it's easier to keep it sliding then it is to start it moving in the first place...
918757
because the moistness causes friction
517904
You can call it wind resistance or skin friction.
1061942
Friction due to atmosphere saves us from the meteors coming to earth, they are burned due to heat generated by air friction.\nFriction helps us walk and helps the working of brakes.\nThere are many to put here, refer some standard Physics books.
171292
The coefficient of friction always involves two materials (or two samples of the same material).  For example, if a sample of one material is placed on an inclined plane of the secoond material, and one end of the plane is lifted, the sample should begin to slide at some angle depending on their coefficient of friction together.  Materials with a low coefficient of friction (suchas ice on teflon) will slide much sooner than materials with a higher coefficient of friction such as steel on wood.
979447
Let's see:\nThe triboelectric effect is only related to friction because they both involve adhesion. However, the effect is greatly enhanced by rubbing the materials together, as they touch and separate many times to create an electric charge.\n\nSo, yes.
278543
that depends on which ceramic you're talking about.  There are hundreds of different ceramics which will interact with steel in different ways.\n\nAlso, the coefficients of static and kinetic friction are different
609002
It doesn't actually come in contact with anything to cause friction.  When a "machine" makes sound, it is made from the moving parts as they hit or rub against one another.  Since a moving pendulum is relying on gravity and its own weight for the arc movements, it doesn't have anything to rub against.
443615
Friction is hte result of Newton's law which says that to any action there is an opposite and equal reaction. Friction is the result of the interlocking of uneven parts of two substances. So you can understand what would happen if there was no reaction to an action. There would be no football, hockey, swimming, baseball, and all other sports.
136353
If you consider a model in which both surfaces which cause friction have crusts and troughs, and their interlocking causes the frictional resistance, then it is explained as follows.\n\nThe lubricant molecules fill up the troughs in both surfaces and make them more or less even, and hence there is less interlocking among the two surfaces, and so less friction.
919106
They all involve friction, but I think you mean which has the most force due to friction, right? :-&#92;  If so, I believe the answer is that they are all the same.\n\nIn simple situations, the frictional force created by sliding two surfaces against eachother is given by:\n\nf = u * N\n\nWhere u (mu) is the frictional coefficient (an experimentally-determined constant) and N is the normal force, which is mg (mass times accelleration of gravity) if the surface isn't tilted.\n\nSo, assuming the frictional coefficient is the same for all sides of the book, there is no reason why changing the sides would make a difference.
143456
I think "µs" and "Ms" are both the coefficient of static friction; they're just in different notations. "~" means "is similar to". The first equation is just saying that the coefficient of static friction and coefficient of kinetic friction are similar quantities: static is for non-moving contact surfaces, and kinetic is for moving contact surfaces.\n\n"Mk = f (v,m)" just means that the coefficient of kinetic friction is a function of both mass and velocity. This means that the coefficient is dependent of both mass and velocity (if either of them change, the coefficient will change also). It's important to note that mass and velocity are not dependent on each other.
1022513
You probably mean "identify the frictional force acting on this object." Since we don't know what the object is, we can't really help you...
656278
tepends on the type of tension...
540441
Depends on what friction we are taking into account:\n\n1)Friction from the road: The frictional force acts in the same direction as the diection of the movement of the bicycle, because it acts at the point of contact of the tyres and the road and at that point the movement of tyres is tangentially opposite to the movement of the bicycle, and thus the friction force always acts opposite henceforth it acts in the same direction of the movement of the bicycle.\n\n2)Friction from air: Air friction will act opposite to the motion of the bicycle.