At first sight, excessive friction force is harmful. It reduces the efficiency of mechanisms, wears out details. But there are cases when friction force needs to be increased. For example, when swing wheels it is necessary to improve their coupling with the road. Look how it can be done.
Instruction
1. To understand how to increase friction force, remember what it depends on. Consider a formula: Ftr = mn where m – coefficient of friction, N – force of reaction of a support, N. Sil of reaction of a support, in turn, depends on weight: N=G=mg where G is body weight, N; m – body weight, kg; g – acceleration of gravity, m / с2.
2. From a formula it is possible to draw a conclusion that friction force depends on friction coefficient. The coefficient of friction is defined for each couple of interacting materials and depends by nature material and quality of a surface.
3. Thus, the first way to increase friction is to change material of the sliding surface. Probably, you noticed that in one footwear it is almost impossible to move on a damp tiled floor, and in another you do not feel any inconveniences. This results from the fact that soles of boots are made of various materials. Slippery footwear has low coefficient of a sliding friction of a sole of rather damp tile.
4. The second way is to increase roughness of a surface. An example - winter tires for the car have more relief protector, than summer. At the expense of it on the slippery winter road the car can move surely.
5. The third way – increase in weight. Apparently from a formula, friction force directly depends on weight. It explains why it is in some cases easier for loaded car to get out of dirt, than to that with light baggage. This rule works at a certain quality of soil – to the viscous, marshy soil the heavy car will sink more, than easy.
6. The fourth way – removal of lubricant. Present the conveyor of the technological line consisting of the rotating rollers on which the tape is tense. Rollers of the conveyor begin to slip according to a tape if they are polluted. In this case dirt works as lubricant. Having cleaned mechanism details, you will increase friction force and will increase equipment efficiency.
7. The fifth way – polishing. Having polished a surface, you can increase friction force. This results from the fact that at contact of the polished surfaces forces of an intermolecular attraction join. For example, it is very difficult to move apart two sheets of glass put together.