10 Examples of Static and Dynamic Friction

Friction

The friction It is a force that exists between two surfaces in contact and that opposes the movement. When an object moves on a surface, it must overcome a force that opposes this movement. If the object is pushed for example and then left free, this force, also called friction, will be responsible for its speed to decrease or even for it to slow down.

Physicist Arthur-Jules Morin studied this concept, and coined the coefficient of friction. This coefficient is characteristic of each pair of materials in contact and is defined as the ratio between the friction force and the force normal to the sliding surface and therefore is dimensionless.

Although some bodies may appear smooth, if viewed microscopically they have imperfections or roughness at the contact surfaces. It is these imperfections that are responsible for the friction.

Types of friction

They are often differentiated two kinds of friction force, according to the moment of movement in which it occurs:

Examples of static friction

1. A very heavy box resting on the ground is difficult to start to move due to static friction.
2. It is easier to start sliding a wet plastic than a dry one since the second has more friction than the first.
3. Friction toys that mimic the behavior of force in the case of vehicles, but in a static way.
4. The feet against the ground, when walking. Static friction makes the foot not move with respect to the ground, when it moves, it is when the friction is dynamic or does not exist and we skid.
5. The wheels of a bicycle against the ground. All wheels work thanks to static friction. Each point of the wheel is stationary with respect to the ground. It does not slip, allowing the wheel to turn and the bike to advance.

Examples of dynamic friction

1. When we push an object on a table, it slides but eventually slows down due to dynamic friction.
2. When we push any object in order to move it, we slide it on the floor. We have to use more force than we would if the floor were made of ice, because there is friction that opposes the movement of the object.