In this section, we'll take a further look into friction. More specifically, we'll consider the specific types of frictions, the effects that they have on physical objects, and a further analysis into how these forces can be observed quantitatively.
Friction between two solids in contact is largely because of their rough surfaces. If one attempted pushing the blue block, it would be more difficult than if the blocks where smooth. This is because of the interactions between the bumps of the orange and blue blocks that would occur.Friction is a force that affects virtually everything around us in our day-to-day life. To note, friction is a difficult force to analytically consider in many situations. As such, much of the existing research considering friction has been done through experiments and there is still a significant amount that remains unresolved about the force. Despite this, in an elementary sense, friction can be well understood by its general behavior and characteristics.
To describe friction, it is a force which acts against the motion of an object when it is not moving relative to its surrounding medium. This can be found in a wide variety of situations that have already been lightly discussed in previous sections. For this section, we'll discuss friction that is acting when an object is in direct contact with a surface. This is in contrast to when an object is interacting with a surrounding fluid, such as in the case of water or air.
For friction as a contact between two solid objects, there are two specific forms that exist. Firstly, there is static friction. This force maintains an object having stationary movement in relation to its surroundings that it is in contact with. In addition, there is kinetic friction, which pulls an object into having stationary movement with its surroundings in contact.A visual of a block sliding because of an applied force overcoming static friction.To introduce these terms, refer to "Friction Intro" by monkey butler (right). In this map, a red block is resting on a rough wooden floor where friction can be significant. Over time, an increasing force in the rightward direction is applied onto the stationary red block. This applied force is canceled by the presence of an equal static friction in the opposite direction such that . Eventually, there is an applied force to the right that is strong enough to cause for , making the block accelerate towards the right.
Once this happens, the block begins traveling over a region where there is a weaker applied force than the force that caused the block to begin relative motion. Still, the block is able to continue moving at a constant velocity where . This is because of the applied and kinetic frictions force canceling each other in this region.
From the information in the video, we can begin to model the magnitude of the static and kinetic friction as a function of time during the experiment, as diagrammed below.
A player-maneuvered koi fish is slowly swimming around in a pond.Suppose a bullet train is gradually slowing down while in motion due to friction in the map "Bullet Train" by Potassium7. Assume that:
The train is traveling along a flat surface.
The train has an initial velocity of in the leftward direction
The train accelerates at a rate of before arriving at a stop.
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