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

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113 views

Sliding blocks problem

My first post here, so I apologize if this is duplicated elsewhere. It IS a "homework" problem, but it's public domain, a posted exam with answers... http://www.mun.ca/physics/undergraduates/...
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2answers
3k views

Why does friction produce heat?

What causes two objects sliding against each other to produce heat? Why don't they generate visible light or something else?
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1answer
636 views

Rolling a ball into a cone; what should the forces overall be?

This is my solution to finding angular displacement/velocity/acceleration on cone so far. Consider a cone, with an apex of half-angle $\psi$ pointing down, and a height of $h$. If I roll a ball into ...
3
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1answer
137 views

Pressure loss in an infinite pipe

I feel lost in this problem. I know pressure loss occurs in a pipe flow due to friction. Say given a constant diameter pipe, if we keep lengthening the pipe horizontally, and static pressure will ...
3
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1answer
276 views

Heuristic equation for Friction force between materials

I'm programming a game where different types of objects will be sliding over different types of terrains (Top-down in two dimensions). At my current level of physics education we are given the ...
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1answer
44 views

Simple Disk rolling with slipping on a horizontal plane

This is the first time I've encountered this scenario. I want to understand how to handle it. Since the disk is slipping, what would be the work done by the frictional force? What is the ...
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1answer
102 views

Why do icebergs move perpendicular to the wind?

I know it has to do with to Coriolis force and the Ekman layer but I didn't really understand the explanation. From Wikipedia: "Ekman transport, part of Ekman motion theory first investigated in ...
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2answers
32 views

Forces on body above body moving at constant velocity [on hold]

Let's say the system is moving at constant velocity. What are the forces applied on B? Is there a static friction force? I find it hard to imagine what is happening to object B. $\Sigma F$ is $0$ on A ...
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0answers
40 views

Friction and movement in a system with body above moving body in newtonian mechanics [closed]

I have a problem in analyzing movement with friction involved. I do not know how to correctly analyze systems as such and what is the correct view. I have tried to answer the several question below. ...
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1answer
37 views

understanding kinetic friction [on hold]

I have a pen on my table. I apply force horizontally to my pen. The force I apply is stronger then the maximum static friction so it moves. I move the pen at constant velocity. Now if we look ...
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0answers
37 views

All about Frictions. (Help me) [closed]

A 20-kg body is on a plane inclined at 60° from the horizontal. The coefficient of friction is 0.22. What force at 30° with the plane will cause the body to move upward at a uniform speed? 2.A block ...
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1answer
28 views

Conservation of Energy with Rotation Caused by Friction

A book that I am using to study poses the following problem: Suppose you wish to use a spring with a force constant $k$ to launch a spherical ball or radius $r$ and mass $m$ up a ramp of inclination ...
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0answers
17 views

Static Friction and Dynamic Friction [closed]

Two magnets are moving in opposite direction. Whether the friction occur in between them or not? And explain it briefly.
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0answers
19 views

triboelectric effect at a liquid-liquid boundary?

In reading up on the triboelectric effect, most experiments deal with solid-solid interfaces. I've found some studies regarding solid-liquid boundaries, and even some engineering manuals outlining the ...
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6answers
6k views

Force required to drive car

From what I know of Newtonian Mechanics, if an object is moving at a constant velocity, the net force acting on that object is equal to zero. If there is friction, then the applied force required to ...
3
votes
1answer
3k views

What is the direction of the friction force on a rolling ball?

Suppose you have a solid ball on a horizontal table. What is the direction of friction force when the ball I pushed horizontally and starts rolling? Why is the direction of friction as it is? Which ...
4
votes
3answers
356 views

How does mass affect the distance a ski jumper travels

I did an experiment to explore this. My results found that their is an optimum mass of a ski jumper. I am unsure about the maths behind this. Can anyone help.
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1answer
137 views

How to calculate torque needed to rotate a ring held captive between two parts with a known compression force?

I'm wondering how to find the torque needed to rotate a ring that is held captive between two plates with a known friction coefficient, radius, and compression force. I'm assuming that the mass of the ...
0
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2answers
66 views

Minimum force needed to keep the book from slipping?

I would just like to know if my answer to part C is correct because I am confident in parts a and b, Also note that 51.5N is the wrong value for P. P=515N. Ok so since P= normal force, this means ...
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1answer
35 views

Why is oil more slippery than water? [duplicate]

It is very well known that the higher the viscosity the higher the resistance offered. But why do we slip more on oil as compared with water even if oil has higher viscosity than water?
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0answers
51 views

What would be the optimal diameter of gold grains if you want to fill a pool with them and swim in it?

I was wondering, if I were to fill a pool with gold/gold dust, what would be the optimal diameter of the grains to minimalize the friction to a point at which you would be able to swim in it ((and if ...
2
votes
2answers
23 views

Friction in absence of normal reaction(in the context of macroscopic picture)

Take two flat non-smooth($\mu \neq0$) surfaces and rub them against each other .You feel the friction as you are doing work to displace them relative to each other. We usually think that friction ...
0
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2answers
49 views

Verifying directions of forces during pure rolling?

Let us take a cylinder on a rough horizontal surface. The cylinder undergoes pure rolling A vertical downward force acts on the cylinder to produce a clockwise rotation. The point at which it acts ...
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1answer
151 views

Accelerated pure rolling and friction

I know that if a body is pure rolling with no acceleration then friction acting on it is zero. But what about if the CM has an acceleration? Then can we say that friction is present? Suppose that ...
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1answer
171 views

Rolling Friction Problem

The handbrake of a vehicle of mass $1.5\ \mathrm{tonnes}$ completely fails while it is parked on a $30^\circ$ slope. It rolls $20\ \mathrm{m}$ down the slope before colliding with, and locking on to, ...
4
votes
1answer
320 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 ...
3
votes
1answer
19 views

Finding the coefficient of static friction on slope

My Problem 1.0kg block is sitting on a horizontal incline plane. The plane is tilted into the block begins to slide. You notice that the plane is inclined at an angle of 32 degrees above the ...
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3answers
9k views

Assuming everything else is equal, which will stop first: a heavier car or a lighter car?

If the friction from brakes, wind resistance and all such factors remain constant, which will stop first? A heavier car or a lighter car? How will the momentum of the car and gravitational pull on a ...
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1answer
61 views

question on friction, 3 blocks placed one upon another

A 10 N force is applied on the 3 kg block. What are the accelerations of the 2 kg block, 3 kg block and 7 kg block? Take the value of g=10m/s^2. what is the acceleration of each of the block ? ...
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1answer
574 views

Block Sliding Down a Plane (Perpendicular Velocity)

I'm having trouble understand the concepts for this problem. Here's the problem: A block is placed on a plane inclined at angle $\theta$. The coefficient of friction between the block and the ...
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1answer
50 views

Why do we assume Kinetic friction to be constant?

My Physics teacher told me that friction exists because of bonds made between the surfaces of two objects. As we try to move an object, we break the bonds and this causes release of energy which is ...
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3answers
295 views

Can friction change the resonance frequency of a system?

I am simulating the transient response of a mass-spring-damping system with friction. The excitation is given in the form of a base acceleration. What I am not sure about is: can the friction change ...
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3answers
175 views

What happens to the coefficient of friction as the normal force increases?

Does the frictional force increase as the normal force increases, or does the coefficient of friction get smaller in value?
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2answers
60 views

Will there be friction?

Is there friction between rough surfaces only (figure below)? If we have two perfectly (mathematically) smooth surfaces, will there be friction between them (figure below)?
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1answer
159 views

Friction because of Earth's rotation

Is there some force of friction that acts on bodies due to rotation of Earth?. We all know earth is an non inertial frame. If there is some frictional force is there some way to prove it?. What I mean ...
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1answer
73 views

How is this Lagrangian derived? (Lagrangian with an exponential function)

In the second answer of this post, Euler-Lagrange equations and friction forces I see a normal Lagrangian (T-V) times an exponential function. $${\cal L}=e^{t\gamma/m}\left(\frac{m}{2}\dot{x}^2 -U(t,...
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1answer
213 views

How can angular velocity be constant even when there is a torque by friction?

A cylinder at rest lying on a rough ground is given an impulse which imparts a translational velocity (no angular velocity) to it. The question goes ahead with finding time after which rolling starts ...
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1answer
250 views

Inclined plane, circular motion and the friction

Suppose we have a cylinder on an inclined plane of mass $m$ and radius $R$ moving without sliding (so that $\varepsilon = a/R$). Why is the friction $F$ causing the circular motion sometimes lower ...
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0answers
47 views

Bigger tire/Smaller Tire

On a track, bigger tires have more contact therefore more traction. However, it comes at a cost of more unsprung weight. Therefore, the 0-60 time is slower as tested by Car And Driver. This was tested ...
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2answers
150 views

Friction to just move the blocks [closed]

Two blocks each of mass $m$ are placed on a rough horizontal surface and connected by mass-less in-extensible string as shown.The coefficient of friction between each block and ground is $\mu$ What ...
0
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1answer
44 views

Friction in circular motion?

Let us imagine a car (or just a block) moving in uniform circular motion with radius $R$ with velocity $v$, on a flat surface. It is obvious that friction is the only force capable of providing the ...
9
votes
1answer
953 views

Why do you hear an acute sound when you rub your shoe on the floor?

Sorry for the silly question, but I've been wondering about this for quite some time. After raining when I get home I rub my shoe's wet outsole on the floor and I hear an extremely acute (high pitch) ...
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1answer
20 views

Reducing coefficient of friction by vibrations?

Very simply put, if one places a block of some material on a level surface and pushes it horizontally, a certain coefficient of friction is measured. If one tightly couples an oscillator of some sort ...
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votes
6answers
32k views

Water pressure calculation for a volume of water at a given height

I'm looking to create a rain harvesting system. I have a 275 gallon IBC tote that is 48" x 40" x 46". I have an adapter for a 3/4 garden hose at the bottom of the IBC tote. I'm trying to figure out ...
3
votes
2answers
445 views

Why do racing tires (slicks) provide more traction with the road?

Google: By eliminating any grooves cut into the tread, such tires provide the largest possible contact patch to the road, and maximize traction for any given tire dimension. My understanding is that ...
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2answers
88 views

Why is it harder to open the cap on a bottle than to close it tightly?

In my experience it's harder to turn the tap off a bottle than to put it tightly on. Why?
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3answers
120 views

Velocity of a body in a pulley problem involving a spring fixed to the ground

So the picture shows the whole situation. My question is, how do you find the velocity of the object after it had descended 10 cm (0.1 m) ? Pulley's radius 0.2 m, moment of inertia 0.2 kg/m I have ...
1
vote
2answers
89 views

Horizontal rolling without slipping

I'm trying to find the friction coefficient that makes the body roll without slipping but I just can't reach a value. The force is applied on a small central disk of radius $r=0,03\, m$ and mass $m=0,...
0
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1answer
25 views

The directions of the frictional force acting on the cylinder while ascending and descending cylinder

A cylinder rolls up an inclined plane,reaches some height,and then rolls down without slipping throughout these motions.The directions of the frictional force acting on the cylinder (A)While ...
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2answers
49 views

Friction, Dynamics question

In the given question $F=2t$ where $t$ is time in seconds for which the force has been applied. Friction exists only between $A$ and $B$ with coefficient of friction $\mu=1/2$. Here we can easily see ...