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

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Calculate coefficient of friction from deceleration with and without conservation of energy

How can I solve the following problem? A block that moves at the speed of 120 cm / s keep going for 70 cm before stopping. What's the coefficient of friction between block and table calculated ...
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101 views

Pseudoforce and friction: confusion

Consider the following situation. A block of mass $M$ is resting on a rough horizontal ground, and a frame is moving towards the right horizontally with an acceleration $a$. Suppose the coefficient of ...
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67 views

Modeling a stool with three legs pushed on one leg

If a stool with three legs is pushed (horizontally) on one leg in the direction of the axis passing through the other two legs, it starts both moving and rotating. Is it correct to assume 1/3 of ...
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361 views

Moving wedge and pulley system

A wedge of mass $M$ rests on a rough horizontal surface with coefficient of static friction $\mu$. The face of the wedge is a smooth plane inclined at an angle $ \alpha$ to the horizontal. A mass ...
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2answers
138 views

Does distance traveled by a vehicle after its engine has been switched off depend on its mass at all?

A vehicle moving with some velocity on a rough horizontal road finally comes to rest after its engine has been turned off. Intuitively, it seems a vehicle with greater mass would stop first because it ...
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3answers
319 views

Why doesn't a block rotate due to friction?

In a horizontal surface, a block (cube) is sliding due to a sudden push. When the block slides, there is frictional force which is acting on the block. Frictional force will have a torque around ...
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277 views

Why neglect friction when computing torque?

There is a block of wood on a plank, with friction, and the block is moving down with uniform speed. They are asking what is the torque acting through the center of the block. My doubt is that ...
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87 views

Friction fire lighting

Having watched a few youtube guides on making a fire by friction, namely the spindle and fireboard method, I've heard many of the instructors talk about how the shape of the spindle at its ends should ...
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1answer
259 views

Calculating the time to stop a wheel with friction [closed]

I'm trying to solve the following problem, but i have no idea how to begin. A wheel of mass $M$, radius of gyration $k$, spins smoothly on a fixed horizontal axle of radius a which passes through ...
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110 views

Can a magnetic field hold a state of supercavitation if a magnetic field could be placed inside of the bubble of the supercavitation?

I have a question that I am just curious about. Two principles: Magnetic fields and Magnetic susceptibility Supercavitation is the use of cavitation effects to create a bubble of gas inside a ...
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1answer
88 views

Shaking water inside bowl causes waves but why does the water stabilize?

Suppose you shake water inside a container, then at first the waves goes up and down strongly but they gradually dissipate. What makes them dissipate?
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331 views

Conservation of Angular Momentum and linear velocity

I have a problem where a cylinder is moving on a horizontal surface, starting with velocity $v_0$. It is given that its radius is $10\text{cm}$, its mass is $200\text g$ and the coefficient of ...
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3answers
5k views

Does the contact area affect friction forces?

I recall studying a law of friction some years ago, in engineering school. All I remember is that when first approximation was taken, the popular $f=k \times N$ was derived. What could that be? Or if ...
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605 views

Mechanics question (a block on top of a block) [closed]

This question is very similar to this one here. A block of mass $m_1$ is placed on another block of mass $m_2$ lying on a smooth horizontal surface. The coefficient of friction (static and ...
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1answer
4k views

Coefficients of friction for steel, aluminum & polymers

I am trying to analyse the problem of sticking an aluminum piece to a stainless steel piece only with pressure. The holding capacity of the system is determined by the static friction between the two ...
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1answer
4k views

Work done by friction

Suppose we have a block of mass $M$ and we are moving it up a curve, very slowly ($a=0$). The surface is not smooth, and coefficient of friction is $\mu=\mu_s=\mu_k$. To move the block we apply a ...
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74 views

friction on atomic scale

I am getting into friction on an atomic scale. For instance, take two rigid layers of atoms of the kind A that are placed on top of each other, just like putting two boards of wood on top of each ...
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3answers
2k views

Preventing a block from sliding on a plane (with friction)

Assume a small square block $m$ is sitting on a larger wedge-shaped block of mass $M$ at an upper angle $\theta$ such that the little block will slide on the big block if both are started from rest ...
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911 views

Overcoming Friction

Let's say a box is moved by attaching a rope to it and pulling with an applied force at a certain angle. Now, let's say that this is being done on an inclined ramp. How would I find the acceleration? ...
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264 views

Friction between atoms in spring

if i doing experiment on spring-mass system in vaccum,if i pull the to some extent (within elastic limit of spring) & let it go,will the system oscillate indefinitely? (neglect contact frictions ...
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356 views

What controls whether a ball will skid or roll?

A billard ball is struck with a cue. The line of action of the applied impulse is horizontal and passes through the center of the ball. The initial velocity $v_0$ of the ball, its radius $R$, its mass ...
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211 views

What is the origin of nonconservative force?

My understanding about conservative force is a force that its work is independent of path such that we can construct another form of the work called potential to make our life easier. For friction, ...
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2answers
636 views

Is my understanding of the mechanics of skidding correct?

I'm trying to understand the mechanics which determine if a car making a turn will skid. Are the following correct or incorrect: A vehicle making a turn will skid unless the centripetal force is ...
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499 views

How to model water flow with and without friction against other objects?

I am interested in modeling water flow including boundary flow (with friction) against other objects in the path of the water flow. I'm not a physicist but I am interested to learn the relevant ...
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1answer
451 views

What conditions must be met for a ball to roll perfectly down an incline without slipping?

What conditions must be met for a ball to roll perfectly down an incline without slipping? A mathematically rigorous definition, please. I honestly don't know where to begin with answering this ...
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170 views

If a puck on ice deccelarates, is its speed “v = v0 - t * a” or is it “v = v0 -k * v0”?

I've been wondering about a puck sliding on ice or a puck in an air hockey table game. If a puck is hit and we start watching it as soon as it has reached its maximum speed and starts becoming slower, ...
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Why don't things balance after they stop spinning?

When I spin a penny, I spin it on its "edge" (circumference). So why is it that when the penny inevitably stops spinning, it never comes to rest on its edge, instead falling onto one of its faces? It ...
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45 views

Showing that a mass moves a half cycle

Consider a mass $m$ at position $x(t)$ on a rough horizontal table attached to the origin by a spring with constant $k$ (restoring force $-kx$) and with a dry friction force $f$ $$\begin{cases} ...
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58 views

A block sliding down a ramp lab (with friction), I keep getting a higher final energy than initial

A block of 55 g is sliding down a ramp of 35 degrees of inclination. The hypotenuse of the ramp is 63 cm and the height is 36 cm. vi = 0 as the block starts at rest. I did 3 trials of letting the ...
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34 views

Are coefficients of friction invariant by switching the materials?

I don't have the ability to make the experiment to answer these questions : Let $A$ and $B$ be two materials. Is the static coefficient of friction of $A$ on $B$ equal to the static coefficient of ...
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32 views

How much energy is saved when using luggage with wheels? [closed]

How much energy is saved when using luggage with wheels as opposed to carrying the luggage? Thanks.
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32 views

direction of friction on an object rolling with constant speed

Although there are many questions similar to this, but none of these specifically talk about the situation with constant speed. A wheel is rolling on a horizontal plane (having some friction) ...
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1answer
29 views

How to mute Sliding Friction

I solve rubik's cubes and do it a lot. However, a lot of people around me get annoyed when I do it because it gets really scratchy when I go fast. I know this is because of the sliding friction ...
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65 views

Maximum angle for highway lane change

I am preparing to fight a traffic ticket from a speed camera. There is a lot more to that story, but the info I need right now involves the angle at which a car can change lanes, in terms of vehicle ...
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20 views

What is happening kinematically to a car on an icy turn? [closed]

I am stumped on a conceptual homework question that involves rotational kinematics and friction. Consider a car traveling along a road that encounters a turn covered in an unseen layer of ice. ...
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37 views

A Question on Friction [closed]

And yes, this is not a homework thing.Here's my working.
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96 views

Why does the mass of an object on a frictionless surface matter?

I'm given a physics problem about a climber hanging over a cliff and attached by rope to a rock on level, frictionless ice. The goal is to find the acceleration of the pair. After working out the net ...
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46 views

The behaviour that saves more energy/ petrol when driving down-up-hill [closed]

This question is in a way a follow-up of this one: Can a car get better mileage driving over hills?, it is similar to that, is no engineering question and is in no way a homework problem, I'd like you ...
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22 views

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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1answer
32 views

Is rolling friction exists only when one body rolls over a plane surface? [closed]

Suppose We have a circular object (A) and at its centre an circular object (B) of the adjusting size is fitted and then the object (B) (axle) is rotated such that it remains in contact wholly with the ...
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2answers
74 views

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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76 views

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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25 views

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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64 views

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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1answer
47 views

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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32 views

Is weathering a form of friction?

Suppose I have a surface out in the wild somewhere. Let's suppose further that over time, this surface is eroded due to any typical form of erosion / weathering. Is this weathering due to a cumulative ...
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1answer
47 views

Why, in a car taking a sloped curve, friction is perpendicular to the car

In solving the problem we usually use the friction as the centripetal force, but I could never understood how is this possible. I understand that if a car is making a circular motion, some centripetal ...
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1answer
37 views

How to calculate heat generated from cosmic dust in space? [duplicate]

Say I have a spaceship, and I'm flying it through space at a constant high velocity V. The spaceship is pretty large (big surface area). In space however, there is cosmic dust scattered throughout ...
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730 views

Tension Problem: Solve for T for two sliding blocks connected by a string [closed]

The problem: Two blocks made of different materials connected together by a thin cord, slide down a plane ramp inclined at an angle θ to the horizontal as shown in the figure (block B is above ...
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30 views

Why do skidding wheels have less traction than non skidding wheels? [duplicate]

I do not understand in terms of coefficients of friction why this happens? From my understanding the ground and the tire still have the same coefficients of friction right? So why is there less ...