# Understanding Friction: Causes and Confusions in Physics Explained

• shayrgob
In summary, the presence of an applied force, such as gravity, is necessary for an object to remain on a conveyor belt. The coefficient of friction and the type of surface used on the belt can also affect the static frictional force and the object's ability to stay in place. If the surface is smoother, the object may slide down due to dynamic friction. However, even in this scenario, gravity is still considered the applied force.
shayrgob
In my physics book it says: "If there were no applied force (F), then Static friction force will be 0."

What confuses me is this, what if an object was sitting on a conveyer belt moving at a 30 degree angle, for instance. What causes that object to remain on the conveyer belt? obviously the friction between the object and the belt? Am i mixing up coefficient of friction and static frictional force?

Gravity then plays the role of applied force (i.e, a force from somewhere else acting upon the object ALONG the surface).

yeah but what if you change the material being used for the conveyer belt? Then obviously more variables (besides the weight of the object) are introduced. Let's say that a smoother surface is used. The object will now slide down.

How does that change gravity from being the "applied" force which was what you were asking about?

Yes. That's dynamic friction. [response was to shayrgob]

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Even if the object slides down, graviry is still to be regarded as the "applied" force.

Cyrus said:
Thats because an object on a conveyor belt is not stationary, relative to an Earth fixed frame.

wanna elaborate?

Sorry, Arildno already answered your question. I answered something you did not ask, so I deleted it. What I said is not wrong, its just not addressing your question. (Find out the answer to your question first, before moving on to what I said. I don't want to confuse you).

## 1. What is friction?

Friction is a force that opposes the motion of an object when it comes into contact with another object or surface. It is caused by the irregularities in the surfaces of two objects rubbing against each other.

## 2. What are the different types of friction?

The three main types of friction are static friction, which occurs when two objects are at rest and trying to move past each other; kinetic friction, which occurs when two objects are in motion and rubbing against each other; and fluid friction, which occurs when an object moves through a fluid, such as air or water.

## 3. What are the factors that affect friction?

The factors that affect friction include the roughness of the surfaces in contact, the weight of the objects, and the amount of force pushing the objects together. Other factors such as temperature and the presence of lubricants can also affect friction.

## 4. What role does friction play in everyday life?

Friction plays a significant role in our daily lives. It allows us to walk without slipping, helps us grip objects, and allows vehicles to move on roads. However, it can also be a hindrance, causing wear and tear on machinery and making it difficult to move objects.

## 5. How can we reduce friction?

Friction can be reduced by using lubricants, such as oil or grease, to create a smooth surface between two objects. Using smoother surfaces and reducing the weight or force of objects can also help to minimize friction. In some cases, adding rollers or wheels can also reduce friction by allowing objects to move more easily.

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