Friction is a force that opposes the movement of an object. To stop a moving object, the force must act in the direction opposite to the direction of motion. For example, if you push a ball lying on the floor, it will move. The force of the push moves him to another place. Gradually, the ball slows down and stops moving. The force that opposes the movement of an object is called friction. In nature and in technology there are a huge number of examples of the use of this force.
Friction types
There are various types of friction:
- A skate blade moving on ice is an example of slipping. When the skater moves along the rink, the lower part of the skates touch the floor. The source of friction is the contact between the surface of the blade and ice. The weight of the object and the type of surface over which it moves determine the amount of sliding (friction) between the two objects. A heavy object puts more pressure on the surface over which it slides, so sliding friction will be greater. Since friction arises due to attractive forces between the surfaces of objects, its quantity depends on the materials of these two interacting objects. Try skating on a smooth lake, and it will be much easier for you than skating on a rough gravel road!
- Friction of rest (cohesion) is a force that arises between 2 contacting bodies and prevents the appearance of movement. For example, in order to move a cabinet, hammer a nail or tie shoelaces, you need to overcome the grip force. There are many similar examples of friction in nature and technology.
- When you ride a bicycle, the contact between the wheel and the road is an example of rolling friction. When an object rolls on the surface, the force required to overcome the rolling friction is much less than that required to overcome the slip.
Kinetic friction
When you pushed a book on a table and it moved a certain distance, then it experienced friction acting on moving objects. This force is known as the kinetic friction force. It acts on one surface of the other when two surfaces rub each other because one or both surfaces are moving. If you put extra books on top of the first book to increase the normal force, the force of kinetic friction will increase.
The following formula exists: Friction F = μF n. The kinetic friction force is equal to the product of the kinetic friction coefficient and normal force. There is a linear relationship between these two forces. The kinetic friction coefficient relates the friction force to normal force. Since this is a force, the unit for its measurement is Newton.
Static friction
Imagine you are trying to push a sofa on the floor. You push it with a little force, but it does not move. The static friction force acts in response to the effort, with an attempt to cause the motion of a stationary object. If there is no such force on the object, the force of static friction is zero. If there is a force trying to cause movement, then the second will increase to its maximum value before it is overcome and the movement begins.
The formula for this type is: Friction F = μsF n. The static friction force is less than or equal to the product of the static friction coefficient μ (s) and the normal force F (n). In the example of a sofa, the maximum force of static friction balances the force of the person pressing on him until the sofa begins to move.
Friction coefficient measurement
What determines the friction force? In nature and technology, the materials from which the surfaces are made play a role. For example, imagine you are trying to play basketball while wearing socks instead of athletic shoes. This can significantly worsen your chances of winning. Shoes help provide the power needed to brake and quickly change directions while running on the surface. There is more friction between your shoes and the basketball court than between your socks and a polished wooden floor.
Different ratios show how easily one object can slide compared to another. Their exact measurements are quite sensitive to surface conditions and are determined experimentally. Wet surfaces behave completely differently than dry surfaces.
Physics: Friction by Nature and Technology
You are friction all the time, and you should be glad that this is possible. It is this force that helps to keep stationary objects in place, and a person does not fall when walking. What is friction? In nature and technology, examples can be found at every step. You may not be aware of this, but you are already familiar with this power. It occurs in the opposite direction to the movement, and because of this it is a force that affects the movement of objects.
When you move the box on the floor, friction works against the box in the opposite direction to the box. When you go down a mountain, friction works against your downward movement. When you press the brake in the car and move for some more time, the friction works against your direction of sliding, which ultimately helps to completely stop sliding.
When two objects "rub" into each other, the forces of attraction between the molecules of the objects are established, causing friction. In nature and technology, it can occur between almost any phase of matter - solids, liquids and gases. Friction occurs between two objects, such as a box and the floor, but can also occur between the fish and the water in which they swim, and objects falling in the air. Friction due to air has a special name: air resistance.
The role of friction in nature, technology, life
Friction is an integral part of human experience. We need traction to walk, stand, work and ride. At the same time, we need energy to overcome resistance to movement, so too much friction requires excess energy to do the work, which leads to inefficiency. In the 21st century, humanity has faced the double problem of energy shortages and global warming from burning fossil fuels. Thus, the ability to control friction has become a top priority in the modern world. Nevertheless, many still lack an understanding of the fundamental nature of friction.
Friction in nature and technology (physics) has always been a matter of curiosity. An intensive study of the origin of this power began in the 16th century, after the pioneering work of Leonardo da Vinci. However, progress in understanding its nature was slow, which was hampered by the lack of a tool for accurate measurement. The ingenious experiments performed by the scientist Coulomb and others provided important information to lay the foundation for understanding. Beginning in the late 1800s and early 1900s, steam engines, locomotives, and then aircraft appeared. Space exploration also requires a clear understanding of friction and the ability to control it.
Significant progress in how to apply and control friction in nature, technology, in everyday life, was made through trial and error. At the beginning of the 21st century, a new dimension of nano-scale friction appeared in connection with the use of nano-technologies. The human understanding of atomic and molecular friction is expanding rapidly. Today, energy efficiency and the production of renewable energy require direct attention, while science seeks to reduce carbon emissions. The ability to control friction is becoming an important step in the search for sustainable technologies. That it is an indicator of energy efficiency. If you manage to reduce unnecessary energy losses and increase current energy efficiency, this will give time for the development of alternative energy sources.
Examples of Friction in Life
Friction is a force that is resistive in nature. It impedes the movement of another object, using some force. But where does this power come from? First, it’s worth starting to look at it from the molecular level. The friction that we observe in everyday life can be caused by surface roughness. This is what scientists considered for a long time the main reason for its appearance.
The simplest examples of friction in nature and technology are as follows:
- When walking, the frictional force that acts on the sole gives us the ability to move forward.
- The staircase leaning against the wall does not fall to the floor.
- People tie shoelaces on sneakers.
- Without friction, cars would not be able to ride not only uphill, but also on a flat road.
- In nature, it helps animals climb trees.
There are many similar points, there are also cases where this force, on the contrary, can interfere. For example, to reduce friction in fish, a special lubricant is released, due to which, as well as the streamlined shape of the body, they can easily move in the water.