What is friction? can you share with me?

Question

anyone, please explain to me the existence of frictional force,the advantage and disadvantage of friction, and one more; my last question, ways to increase and reduce friction. Please tell me.. Your answer is really help for.

Answer 1

Friction, force that opposes the motion of an object when the object is in contact with another object or surface. Friction results from two surfaces rubbing against each other or moving relative to one another. It can hinder the motion of an object or prevent an object from moving at all. The strength of frictional force depends on the nature of the surfaces that are in contact and the force pushing them together. This force is usually related to the weight of the object or objects. In cases involving fluid friction, the force depends upon the shape and speed of an object as it moves through air, water, or other fluid.

http://encarta.msn.com/encyclopedia_7615...

Answer 2

1. Newton Laws can explain.

Wherever a object heading to, there will be an opposite force exist.

eg, you move to left, a force ( friction) move to right.

2. Advantage: stop the car. ( friction presents between the road and wheel )

3, Disadvantage: energy-consuming or wasting energy and release heat.

4. Increase : use a rough and small surface thingie

5. reduce : apply lubricant or use a larger surface thingie.