Questions tagged [friction]

The resistance a surface or object encounters when moving over another.

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Is it possible to formulate a Hamiltonian for a damped system? [duplicate]

I recently found out that it is possible to formulate a Hamiltonian for a system with time-dependent coordinates such that the Hamiltonian is not the same as the energy When is the Hamiltonian of a ...
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Finding the acceleration of a mass/pulley system without knowing the direction of the displacement

I have the following question: In the diagram below the mass $m_1$ is moving down the incline . The surface upon which $m_2$ moves is smooth, and the coefficient of kinetic friction between $m_1$ ...
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Can Tension between two blocks on a horizontal plane be discovered in these conditions? [closed]

the bodies are linked by an ideal string, one has m1=10kg & the other m2=20kg The force is known and is pulling horizontally, F=60N on the lighter object the coefficient of friction is said to be the ...
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Equilibrium when it shouldn't be?

I'm doing an experiment that requires me to balance a ring, tied to four strings, in the middle of a force table; in other words, the objective is to set the ring at equilibrium. Each string is ...
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Force needed to hold a book between your hands - not sure about the influence of friction

I'm looking at this problem: A student presses a book between his hands, as the drawing indicates. The forces that he exerts on the front and back covers of the book are perpendicular to the ...
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How can a petrol car require less fuel at 55mph than a lower speed at the same rpm?

It seems to be widely accepted that somewhere around 55mph is the most economical speed to drive in a conventional petrol car. Recently I ordered an EV, and learned that (with the exception of at ...
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Maximum acceleration for a vehicle [closed]

I'm in engineering school and we have a project: we have to build a amphibioues vehicle; I'm looking for a formula. Our vehicle has to go as far as possible with its unique source of energy, a ...
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Question about circular motion of car turning

When we move round a roundabout there is a frictional force between the tires and the road that acts towards the centre of the roundabout in order to produce the circular motion. Why then do we ...
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Role of roughness in friction

In many textbooks static and kinetic friction is explained by surface roughness and interlocking asperities. However this website: http://amasci.com/miscon/miscon4.html#fric which is cited in ...
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Can there be friction unless the objects in contact are not acted upon by an external force?

The definition of friction I read from The book, General Physics written by Henry Crew is that, The resistance which either one of the body offers to the motion is called force of friction". If it is ...
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Why friction is not taken to be varying jointly as roughness of the object along with normal force?

Frictional resistance to the relative motion of two solid objects is usually proportional to the force which presses the surfaces together as well as the roughness of the surfaces. But when we talk ...
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If two bodies move opposite to each other when brought in contact, what is the direction of force of friction?

We know that when a body is at rest and other is dragged over it then a force is produced which opposes the motion and consequently its direction is negative to the force applied on body to produce ...
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If the force of friction is 20 N for a moving body does acceleration increase with the increase of the mass?

A body is moving and the only force acting on it is the force of friction. If we put another body on this moving body somehow the force of friction will increase; does its acceleration change?
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What is a self adjusting force?

What is a self adjusting force? I searched it everywhere on internet but not got my answer and I have no other source to get its answer except this site so please help me.
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Rolling w/o slipping - does a friction force acts in this scenario?

Assume the following scenario of rolling without slipping: A small disk starts rolling w/o slipping at $\vec{r}_{CM}=-9R\hat{x}$ (scenario A) and reaches the bottom of the large hollow disk (scenario ...
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Can a thrown egg chip (or break) a car windshield?

Is it possible to throw an egg with such speed that a car windshield will chip (just like with stone chips?) I have searched around for existing research in the area and have found that the impact ...
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Calculate damping constant / coefficient

I am trying to graphically simulate a series of springs in 2D. Now one of the forces I am stuck with calculating is the damping force. The given formula is $F = -k_d v$. I know that $v$ is the ...
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Why do bowlers rub the ball before bowling in a cricket match?

Why do bowlers rub the ball before bowling in a cricket match? What is the science behind it? Is it because of friction?
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Plastic and Iron - static and magnetic

I'm wondering if when you have a ball that is made out of plastic but has an inner core of metal. Would that ball if given friction produce static? Or would the static from the outerside of the ...
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Direction of friction vector when acceleration is zero

There is a box on a ramp, there is Wx that makes it fall, Tension that pulls it up the ramp (a rope) and Friction. The thing is, how can I determine the direction of the friction? For me, friction ...
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An object is placed on an inclined plane. Does it roll? [closed]

An object is placed on in inclined plane. There may or may not be friction, your choice. My question is, how do we figure out whether or not it rolls? For example a sphere rolls but a cube doesn't.
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Work out friction coefficient using the two material's properties

For a physics engine I am working on, I need to know two object's friction coefficient (for bouncing, collision detection, friction in general etc.). Since this physics engine will have lots of ...
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A more rigid explanation of “path of least resistance”

In order to try to understand the centripetal force and more specifically how it works for cars, I watched this YouTube video: https://www.youtube.com/watch?v=bB6R1rx5bOA The video offers a good ...
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What happens to something impacting a frictionless surface [closed]

If you try to hit a frictionless surface with the hammer at a non perpendicular plane. Would there be a force transfer or something along those lines?
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Rolling on a frictionless pond

I have a doubt about one of the questions in my textbook. Q- You are standing with your bag in your hands in the middle of a friction-less pond. How can you come out of the ice? There is of course ...
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Conservation of energy during rolling without slipping?

Say there's a cylinder laying on a flat surface, and the surface is rested on frictionless ice. Attached to the surface is an engine that is attached via a string to the center of the cylinder, and (...
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Does friction depend on the area of the surface? [duplicate]

Do the frictional forces vary from each other when different objects try to move on a surface? The materials, sizes, shapes are different from each other.
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will frictional force work against the vertical direction of velocity of an object?

We assume that an object is placed on a horizontal plane. If this object is accelerated to vertical direction, will frictional force act against the vertical direction of velocity of object? For any ...
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max speed of circular motion

I understand that it is the static friction force that lets us turn the car around the corner. It provides the necessary centripetal acceleration. Static friction opposes the impending motion of the ...
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Two-linkage under the force and friction

I need to find friction force in this configuration. Book says that $F_{fr}=\mu P.$ but i think that force $P$ is distributes evenly between hinge (A) and sliding block (B), so friction must be $1/2 \...
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Rolling without slipping and friction [duplicate]

When a ball rolling without slipping along an inclined plane reaches the bottom, it has a linear velocity $v$ and angular velocity $\omega\ =v/r$ at the bottom. Then it continues its motion on the ...
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Why do your fingers alternate then meet at the center of mass of the object?

Hold a pen (or pencil, ruler etc.) using your two index fingers with your fingers at the ends of the object. Now move your two fingers toward each other. Assuming the frictional force provided by both ...
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As a car turns around a circle, why does the force of static friction point towards the center of the circle [duplicate]

A car moves along a flat, circular road. It has a tangential velocity to the road, but the car tires change direction and the car experiences a force of static friction causing a centripetal ...
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Is work done in rolling friction?

I am confused by rolling friction. Suppose you have a cylinder rolling which starts at rest at the top of an incline plane and begins to roll down the plane without slipping. Is work done by the ...
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What role does static friction force play for a rolling object? How can I know what direction it points?

Fundamentally, what does a friction force do for a rolling object? I am very confused by the way my textbook explains it. In my textbook , it says: A wheel rolling on a horizontal flat surface at a ...
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Does damping force affect period of oscillation?

In my physics notes, it has been given that the damping force increases the period of oscillation. I am unable to understand this part. How is this possible? The only relation I know is that as the ...
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How does friction help the car to move forward? [duplicate]

Below is the extract from my book. There is a car with four wheel drive system and during acceleration, the engine causes the tires to push backward on the road surface. This push produces ...
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Why speed of block/box reduce when force is acted?

In my physic book there is a question which is as follows;- A food shopper pushes a wood crate of cabbage heads of mass $m$ =14kg across a concrete floor with a constant horizontal force $\vec{F}$ ...
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Calculating work done on a rigid body

How in general does one calculate the work done by some force acting by a rigid body? Do you have to take into account the torque and the translation? For example: Suppose we have a ball rolling down ...
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Efficiency of Bicycle Pedalling

Consider a bicycle with multiple gears. Suppose that you are in a starting position with someone holding your bike upright (so when you start there's no issue with clipping in etc). It's well-known (...
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Is friction acting for average speed if vehicle passing on a banked road?

Roads are usually banked for the average speed if vehicle passing over them. However, if the speed of a vehicle of a vehicle is somewhat less or more than this the self adjusting static friction will ...
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Why is the equation for friction so simple?

The general equation for the force of friction (static or kinetic) is $F_f = \mu * F_N$, where $F_f$ is the force of friction and $\mu$ is the coefficient of friction (its value is dependent upon the ...
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Running Euler's disk in a superfluid

I was considering the toy Euler's Disk, a video can be found here: http://www.youtube.com/watch?v=mVl2CBG_h2s I was interested in understanding the behavior of the disk particularly in vacuum and in ...
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Cause of rolling friction

Can you explain the cause of rolling friction? Can you tell me why, while driving a bicycle, there is less rolling friction when its tyres are fully inflated?
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Dependence of kinetic friction on relative velocity

While I was reading my book I came across a line that tells that there is slight dependence of kinetic friction on velocity of relative motion of the bodies. Can anyone tell me how is this so?
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Frictional loss of matter

How do we account for the loss of matter from an object due to friction ? Is it simply a phenomenon or result of any other process ? Eg :The loss of matter from the rubber tyre
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Inclined pulley with unknown hanging mass: when won't the system accelerate?

We have an inclined pulley with angle of $30° $ a block with mass of $10 kg$ placed upon it and It is attached by a rope over a pulley to a mass of $M_A$ which hangs vertically. If $μ_s=0.4$ and $μ_k=...
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Problem of uncoupling a train

As a kid I have seen several movies, cartoon etc. in which usually one guy just uncouple (unplugs (?), dunno) the rest of a running train and then runs off with the locomotive at full speed and ...
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Can the weight of a bird be measured, considering air friction? [duplicate]

Assume that a bird of mass 1.5 kg is held in a box at height 500m and this setup is placed on a weighing machine. Now, the bird starts to hover in the box pushing the air downwards, and is at a ...
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What forces cause the centripetal acceleration in circular motion on a merry-go-round?

Suppose you stand on a merry-go-round spinning at $f$ revolutions per second and you are $R$ meters from the center. What forces act on you? If you were tied to a rope like in Fig 2 you would follow ...

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