• Telemachus
In summary, the conversation discusses a problem involving a force applied to an object over a horizontal path, with the presence of dynamic friction and an initial acceleration. The object has a mass of 98kg and a normal force of 960N. The acceleration caused by the force is 3.92m/s^2 and the question is how long it will take for the object to travel 10 meters. The solution involves using static and dynamic friction to calculate the acceleration and applying kinematics formulas.
Telemachus

## Homework Statement

I have this doubt, I think its trivial, but I don't know how to express this thing mathematically. The thing is, I have a force F applied to an object of mas m over an horizontal path, under the action of a dynamic friction force. I know that with the force F the object will suffer an acceleration a. Let's suppose the force is F=384.16N, the mass is 98kg, the normal force is 98kg.g=960N, and the static friction coefficient is 0.4 and dynamic friction coefficient is 0.14. The object is over an horizontal surface, so the normal force is equal to the weight. The acceleration that the object will suffer due to the force is 3.92m/s^2. But the force that produces that acceleration its applied just once, so then the acceleration decays due to the dynamic friction. So I want to know how long it will take to the object to travel a distance of 10 meters. How should I proceed? should I consider an initial acceleration? how do I express the action of the dynamic friction at every instant of time?

Bye, and thanks for posting.

You use static friction to figure out if the object accelerates at all. If it doesn't, then dynamic friction is completely meaningless. If it does, then you use dynamic friction to figure out how much it accelerates. From there, you simply use those good old kinematics formulas.

Thanks Planck. I have just realized what I have to do. I just must consider the acceleration given by the force as an initial acceleration.

Bye there!

## 1. What is friction?

Friction is a force that opposes the motion of objects when they come into contact with each other.

## 2. How does friction occur?

Friction occurs when two surfaces rub against each other, creating resistance and slowing down or stopping the motion of one or both objects.

## 3. What are the types of friction?

There are three types of friction: static friction, sliding friction, and rolling friction. Static friction occurs when two surfaces are not moving relative to each other, sliding friction occurs when two surfaces are moving against each other, and rolling friction occurs when an object rolls over a surface.

## 4. What factors affect friction?

The amount of friction between two surfaces depends on the types of materials involved, the roughness of the surfaces, and the force pushing the surfaces together. Friction can also be affected by the temperature and the presence of any lubricants.

## 5. How can friction be reduced?

Friction can be reduced by using lubricants, such as oil or grease, between two surfaces. It can also be reduced by using smoother materials or by decreasing the force pushing the surfaces together. In some cases, adding wheels or other rolling mechanisms can also reduce friction.

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