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

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132 views

Why does temperature change the friction coefficient of my stovetop?

I have a Ceran cooking field at home, it's a glass-ceramic surface with heating coils embedded beneath. When I slide a pan around there's much more friction on a hot plate than on a cool one. Why? ...
5
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331 views

Why does the overhand knot jam but the figure-8 knot doesn't?

After tensioning a rope with an overhand knot in it, it is often very hard if not impossible to untie it; a figure-8 knot, on the other hand, still releases easily. Why is that so? Most "knot and ...
4
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73 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 ...
3
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35 views

Can't identify static and kinetic friction regions

EDIT:I would like to say thank you to those who have commented so far trying to help me. It is really appreciated!! In a project, I am analysing the frictional behaviour of different specimen on a ...
3
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57 views

Lagrangian Mechanics + Account for friction of block

$\newcommand{\dd}{\mathrm{d}}$ I am trying to work out the Lagrangian mechanics for a pendulum problem in order to animate it. I'm working on one of the examples in the Wikipedia page on Lagrangian ...
2
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26 views

Coulomb's static friction in multidimensional case - decide which mass begins to move

Consider a system of N coupled oscillators, under the effect of elastic forces, damping, dynamic and static friction and an external force; for simplicity, let's suppose $N=3$. The friction model is ...
2
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105 views

Can I use the reduced mass principle in a spring-damper system?

http://hyperphysics.phy-astr.gsu.edu/hbase/orbv.html#rm I want to know, if I can use the reduced mass principle to solve a two object spring-damper system. In the books and webpages that I have ...
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193 views

Is there any place you can safely skydive without a parachute?

While trying to explain to someone how a kitten walked away from a fall from a skyscraper I got to wondering if there's any place a human could do that and I find myself out of my depth. The only ...
2
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473 views

Why did increasing the Ackermann geometry in my race car make it faster in corners?

Ackermann geometry is used to account for the different radius arcs that the front tires follow when the steering wheel is turned from center. It's often expressed as a percentage: e.g. 25% Ackermann, ...
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27 views

A trio of spinning marbles

My little brother showed me this devised act in which he stuck three marbles in a triangular pattern When he spun any of those marbles, the triplet would first rotate normally, but moments later, ...
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31 views

In table tennis, is it possible to play a ball in such a way that it does not bounce off the opponents half of the table?

In table tennis you dont need to play over the net, the ball just has to hit the other half of the table. Is it possible to play the ball around the net so that it does not bounce off? My friend and ...
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45 views

Maximum angle that a wheeled body can climb at

I've only recently been introduced to the concept of static vs dynamic friction and I was looking to check my understanding by determining the max angle a wheeled body can climb. In the diagram below ...
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16 views

pulley friction difference between static and sliding surfaces

the pulley friction question for static cases is T2/T1=e^μθ. When the surfaces between the belt and the wheel slide, how can we determine the friction? Is it the same friction? Is there a different ...
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23 views

Ski treadmill materials

This ski treadmill is not much of an incline, but it still allows people to ski and carve out turns. What materials have such a low coefficient of friction, yet allow higher friction at higher ...
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136 views

Friction in Lagrangian formulation

We know the Lagrange equations are: $$\frac{\partial \mathcal{L}}{\partial q_i}-\frac{d}{dt}\left(\frac{\partial \mathcal{L}}{\partial \dot{q_i}}\right)=0.$$ Then, when we add friction in there, we ...
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36 views

work done in observer frame

I had a few questions. 1) Is work done independent of the refrance frame? 2) Suppose a cart-A with rough surface is accelerating with an acceleration a and another cart-B with acceleration b. Now to ...
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190 views

Can iron filings on a magnet be removed using a stronger magnet?

After some experiments, I had some NdFeB permanent magnets "contaminated" with iron filings, sticking to it's poles surfaces/edges - you may have seen that before. There are some working ways to ...
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59 views

Friction of an object falling between two walls

I'm simplifying this problem into 2D for easier understanding. Lets say we have 2 vertical walls separated by distance x. Inside these walls I place an object that is only slightly smaller than x in ...
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593 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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30 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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82 views

How do whitening toothbrushes work?

Certain "whitening" toothbrushes are sold and I was wondering about the mechanisms behind the tooth whitening process. I suspect this is related to the shape and arrangement of the fibres, probably ...
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47 views

Friction effects on ball motion direction when crossing surfaces edges

For a ball rolling from a high friction coefficient surface to an adjacent low friction coefficient surface. When the ball crosses the boundary at an angle, I believe it changes angle of velocity, ...
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245 views

Is it possible to increase the electromagnetic repulsion between two particles?

Given the fact that the force stopping me falling through the ground is the electromagnetic repulsion between the electrons in my feet and the ground, would it be possible to increase this repulsive ...
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116 views

Is there quantitative theory of cutting with edge or blade

I wonder if there is some simple theory of what determine efficiency ( speed, energy end force required ) of cutting by edge ( blade , knife, sword ) At least something phenomenological like in ...
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230 views

Is there any role of steering in turning?

I am aware of the practical requirement of turning the steering wheel to turn a car while going on a straight and even curved road. But in the proofs of turning of car on leveled or banked curves, we ...
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126 views

Finding kinetic friction coefficient

A box is thrown up an incline with degree $\alpha$. the kinetic-friction coefficient is $\mu_k$. the body returns back to its start point. a. prove $\frac{t_{down}^2}{t_{up}^2}=\frac{a_{up}}{a_{...
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781 views

Forces on two boxes

This is a problem from my problem sheet but we haven't yet covered the material or received our books. There is a small box of mass $m_{1}$ resting on a plank, of mass $m_{2}$ and length $L$, which ...
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204 views

Friction From an Object On-Top of a Sliding Object

Consider a block $A$ lying on a flat and frictionless table, and a block $B$ lying on top of block $A$. A horizontal force $F$ is applied to block $A$. If there is no friction between blocks $A$ and $...
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81 views

Modeling of exact stick-slip-friction using Linear complementarity problems (LCP)

Within my master's thesis, I try to model a machine elements and have to model the exact slipping and exact sticking between the bodies. So I noticed that such problems can be formulated as a LCP. ...
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61 views

Modeling Acoustic Lubrication

I thought about posting this question in the Biology StackExchange site but really it is just the application of my question that applies to biology not the core of the question itself. Can anyone ...
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622 views

What is the angle of the string with the vertical?

A heavy uniform sphere of radius $a$ has a light inextensible string attached to a point on its surface. The other end of the string is fixed to a point on a rough vertical wall. The sphere rests ...
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1k views

FPS to MKS usage issues

I'm currently taking a high school physics class and we're doing friction problems now. I've been doing the ones that use MKS perfectly well, but when the problems start to use the FPS system, I'm ...
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302 views

Stoke's Drag Constant

I'm trying to calculate Stoke's drag constant using the equation found here. The system I wish to calculate it for is a mass oscillating vertically on a spring through air. The temperature is 25 ...
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22 views

How does the rolling resistance of sticky tires scale with speed?

If I have a wheel that has a soft tire that sticks to the ground, will the rolling resistance (not the traction of the wheel, I mean how much force it takes to keep it rolling at the same speed) scale ...
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28 views

Pendulum with Viscous and Frictional Damping

I am trying to model a pendulum with both viscous and frictional (Coulomb) damping. The problem is that the viscous damping only occurs in one direction because I am modeling a dashpot that only has ...
0
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41 views

Force conversion in a barrel cam-follower mechanism

A barrel cam-follower mechanism consists of a (cylindrical) barrel with a cam track, a cam-follower (roller) inside of the track, a fork connected to the cam-follower and a guide along which the fork ...
0
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40 views

Find the maximum force P that can be applied for which the blocks do not slide and their respective acceleration

Two blocks are on an inclined ramp of 35 degrees. Block A is on top of block B. Block A weighs 36 lbs and block B weighs 18 lbs. The coefficient of static friction between the two blocks is 0.45 but ...
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38 views

Energy dissipation in spinning wheel

I was given the following question in a test. A spinning wheel A is brought in contact with an identical wheel spinning at identical speed.The wheels slow down under the action of friction.Which ...
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68 views

Where can I find a table of rolling friction coefficients of various materials?

I am looking for the coefficient of rolling friction of a 1.5 cm radius polymer ball rolling on steel. I have been searching all over the Internet for it but I can only find tables of static and ...
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46 views

Apart from friction what can be considered a non-conservative force?

I know that friction is a non-conservative force. My question is if we have any non-conservative forces or other fields in electrodynamics? second part question for a force that conservative we have ...
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47 views

About the formula of pendulum simple

for the modulation and the simulation of a pendulum simple , I'm Find this formula : a(t) = a0 * sin ( sqrt(g/l) * t * Pi/2 ) - [ k/(mll) * cos ( sqrt(g/l) * t * Pi/2 ) * t ) ] ...
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16 views

Increase in temperature of metal piece during filing explain by the Gibb's equation?

When we file the metal the surface of the metal gets worn out in the form of small pieces of metal. The file acts as medium to transpher the energy from the body to the metal piece in the form of work....
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25 views

How to describe the forces on a weblock?

I am trying to figure out the forces on a weblock when two strands of webbing are wound around it. I have made an attempt but would like to know if I am on the right track or not. A short background, ...
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30 views

pulley friction assumptions

I have a dispute with this lecturer I have been given over the equation $T_2/T_1=e^{μθ}$. My opinion is that since it is derived from $T_2=T_1+\text{Friction}$, so the first equation is valid ONLY in ...
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63 views

Rolling Resistance Coefficient

I found that rolling resistance can be expressed with this equation: $$F_\mathrm{rr} = \frac{C_\mathrm{rr} W}{r}$$ Where $C_\mathrm{rr} =$ coefficient of rolling resistance $W =$ normalforce $r =$...
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55 views

Friction forces on car wheel

I know that frictions means a lot for car wheel. I've been looking all around a lot and trying to figure all out. I have found out about Coefficient of friction depends on slip ratio(which I am ...
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54 views

Car wheel's “slip ratio” equation for game

Some of you may know about slip ratio. It is specific ratio that kind of depends on wheel rotation speed, radius etc. and affects friction. Car has the most friction at around 0.05-0.1 slip ratio (...
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23 views

Friction Loop Formulation

I am not a physics guy so I am sorry if my question is too dumb. I want to know if we have two bodies in contact with each other, we often see the force and some displacement in form of a friction ...
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35 views

How to derive friction laws?

How do I derive the laws: $$F_s = \mu_s N, F_k = \mu_k N$$ For static and kinetic friction? It was one of the very first things I was ever taught in a physics lesson, and yet to this day I still don'...
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58 views

Stokes' law and settling particle speed

What are the forces that are exerted when a particle is dragged by air flow in a tube and settles within some distance? Does Stokes' law calculate the net force, taking into consideration of all these ...