1. Does friction always slow down body movements? Explain answer 2. Can I skate on polished marble floor? 3. The body lies on a rough horizontal surface, does the friction force act on it? Justify your answer 4. What are the causes of frictional forces? 5. What methods can be used to reduce the sliding friction force? 6. What methods can be used to increase the sliding friction force?
1. Since the friction force is always directed against the direction of movement, then it opposes the movement, therefore it slows down the speed of the body.
2. No skating on the polished marble floor. A large force of friction between these surfaces, a large coefficient of sliding friction between these surfaces. When skating on ice, when skates rub against the ice due to friction, the ice heats up and it begins to melt. The rubbing surfaces are wetted.
3. Friction does not act on an immobile body of silt. It always opposes the movement of the body, and since the body does not move, there is no friction force.
4. The cause of the friction force is the roughness of the surfaces that interact. There is an interaction of rubbing surfaces.
5. To reduce the sliding friction force, you can make the surfaces that interact smoother, that is, they can be sanded. Lubricate rubbing surfaces with special fluids – oils. The sliding friction force depends on the type of material of the surfaces themselves that interact.
6.Increasing the sliding friction force can increase the number of irregularities on surfaces that rub.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.