Friction Definition and 998 Threads

=================== Now, I can get the solution in the book by writing and solving the force and the torque equations together with the non-slipping relation between the angular acceleration and the center of mass acceleration. However, the book solution only arises if there no friction between...

I've witnessed 1st-hand with my own eyeballs this guy riding an S-shaped path through chicane at Thunderhill East+West 5-mile combined course with front-wheel IN THE AIR! I believe bike is a Yamaha TZ250, 100-120bhp and 200-lbs weight. I conducted an experiment to document behavior of single...

I calculated friction = 1N.But since force is more than maximum friction,therefore lower block will not move and a force of 0.5N will be applied to upper block. Therefore its work done by friction will be W=0.5×6=3 J. But answer given is 1 J. Can anyone help.

Suppose a metal disk is spinning at constant rate of one cycle per second and at a radius of about four inches a small metal block is pressed against the disk. The circumference of the path of the contact is exactly one foot. The coefficient of kinetic friction between the disk and the small...

Hello, do someone have time to help me out with an assignment? My question In the answer sheet they say: What I do not understand is why m is withdrawn from both sides, since I don't see that those represent the same mass. When I did the assignment I thought m at the left side would be the...

Friction is commonly thought to arise from the electromagnetic forces of the atoms at the boundary between two surfaces in contact. However it occurs to me that, in addition to charge quanta, there are also mass quanta present in this system and they could very well play a role. Now, I'm just...

Hello, I have a cuboid on two different surfaces. I am applying a changeable force F to it, but it should stay on the same point / in static friction. I now want to calculate the combined (static) friction coefficient μ_combined out of the two known coefficients of cuboid to surface 1 μ_1 and...

It seems to me that this transition implies going from kinetic friction to static friction. The kinetic friction would apply a torque that would slow down the object's angular velocity, but I'm not sure how this connects to the object suddenly transitioning into rotating without slipping.

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Summary: Relation between deformed foil and friction force Good morning everyone, i have a small leaf or steel that is bent from one side by a Pressure of many bars. in front of the leaf there's a rotating disk, separated by the leaf by a small gap. this leaf, as it deforms, wins the gaps and...

I feel like it would go on the side of the energy the object has where it starts - an object dropped off a cliff would be modeled U - W = K but an object thrown upwards from ground level would be K - W = U. I am not sure though.

(The weight scale = 10 kg). After initial force, now the mass is lowering down at constant speed of 1 m/s. The motor with pulley's radius of 1 meter is exerted 100 Newton m to keep constant V. The motor speed is about 9.55 rpm. * All other weights, inertia and frictions of the system is...

I tried to find the force of friction using the the coefficient of kinetic friction with the equation F=nukmgcos Ѳ. Then I made the force of friction equal to the force of pull. I don't know what I'm doing wrong as I'm getting the wrong answer. I have attached a picture of my work.

Fg = mg = 50 * 10 = 500 N Fn = mg-ma = 500 - (50.0)(1.0) = 500-50 = 450 I don't necessarily know if this is right and I can't seem to find the Ff or coefficient of friction either. Please Help!

I am testing a new note-taking method which I invented recently in order to help filter out irrelevant information and focus on what is actually useful and worth noting down/remembering. I then applied this to the Friction chapter in the tipler/mosca textbook as a way of testing out how this...

So above is the question. The picture below is my attempt at the solution: However the answer at the back of the book suggest that T=1.929s

Hi everyone, I'm trying to derive DC motor differential equations. I have some doubts: I have a viscous friction coefficient in terms of N*m*s. Is it possible to express it in terms of N*m*s/rad? And how? Some exercises show this value in Newton-meter-second and others in...

no idea

Consider a block on a sheet of paper. If the sheet is pulled without sliding the block, who has done work on the block (since it has undergone a kinetic energy variation)? I can not see another force doing work other than the static frictional force on the block.

I think I am on the right path but I'm having trouble cancelling out the mass of the wallet. I drew a free body diagram and know that there are three forces acting on the wallet: gravity, friction, and normal force (including the van's acceleration). The y-component of the friction and normal...

Good morning sirs, let's imagine a cylinder, surrounded on 360° by a coating of the same shape. I can close the 2 half using 2 bolt screws. what's the maximun transmittable torque? here's a scheme: i would to consider the sum of forces as a normal force on the top of the cylinder, producing a...

Homework Statement This is the problem from the book "physics for scientists and engineers..." by Serway, Jewett / Chapter 5, problem 98 Initially, the system of objects shown in Figure P5.93 - is held motionless. The pulley and all surfaces and wheels are frictionless. Let the force F be...

Hi! I'm working in a new area and I'm looking for inputs/suggestions for relevant factors to look into and possible ressource where I can read about this :) I did some tests in a pulley similar to the one below. I had a fixed weight at M2. I started with M1=M2 but added weights to M1 until...

In the situation of a magnet moving towards a flat sheet of copper; why doesn't the copper gain angular moment as the electrons move in concetric circles? The electrons are experiencing friction as they move through the copper.

Homework Statement Hello. I have slope = 45 degrees, at distance 36.4cm (0.364m) object gains 2m/s speed. Need to calculate friction coefficient. Correct answer is ( 0,2). How to calculate? Homework Equations 1) t = s/v "t" - time; "s" - distance "v" - speed 2) S =...

Homework Statement A person of mass ##m## stands at the left end of a boat of mass ##M## and length ##L##. Both the person and the boat are initially at rest. The coefficient of kinetic friction between the boat and the water is ##\mu##. If the person starts moving to the right, what is the...

Homework Statement A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope inclined at 20.0° above the horizontal. The sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is...

Hello everyone. I find the following problem confusing. A board sandwiched between two boards in the figure below weighs 95.5N. If friction exists between the middle and the compressing boards, draw the free body diagram of the middle board. Below I attached the diagram found in the solution...

Homework Statement A water tank with a total mass of m0 is moving on a horizontal road with a coefficient of friction equals to μ. At t=0 water starts to come out of the tank with a velocity equal to u0 in relation to the tank. Each second the mass of water that comes out is λ. Find the...

Homework Statement I am posting the snapshot of the problem Homework Equations Moment of Inertia equations The Attempt at a Solution Now, the pulley has the moment of inertia ##I = 1.5MR^2##. This is strange, since the coefficient of ##MR^2## is less than or equal to 1. So, this means that...

Hello colleagues, I'm designing a simple precision rotational mechanism for angular positioning of an optical element. I need a total rotation travel angle of about 50 deg at a low speed (a few seconds for the full travel) with about 4000 discrete positions over the travel angle. Any systematic...

Homework Statement The 2 objects slid on the incline level without friction. The height difference of the objects at t=0 is 8m. At t'=1.5sec the objects are on the same horizontal level. What is the analogy of M/m? (M is the mass of the left object and m the mass of the right object. *Have a...

In Morin's textbook,he ask a problem of the work done by friction in making body roll if the body initially starts with pure translation (i.e sliding motion). However I didn't get require answer(via Work Energy theorem) and I gave up. I checked solution and I became confused. He tells that...

How do I guarantee that that the friction in the movement of a simple mathematical pendulum is negligible?

Hi, I was recently tasked to build a mini-sumo robot (10x10cm. 500g. the objective is to push your opponent out of a 75cm. diameter arena or dohyo), and I was wondering about the tires that I'm going to use. I want to increase the friction coefficient as much as I can, so I was wondering how to...

Homework Statement Hello, so I currently designing a centrifugal brake, I know how much torque it needs to stop etc just unsure of a few things. How would I calculate frictional torque? I understand that I can use the net torque to determine what torque is needed for equilibrium etc however I...

Homework Statement Correctly present the table of information. The values in the table are deliberately in a wrong format. The calculated Re values have been analysed to have an uncertainty of ± 0.4% and the calculated f values an uncertainty of ± 0.1%. Homework EquationsThe Attempt at a...

Homework Statement The static friction coefficient on an inclined plane is equal to tan(θ). The problem requires me to prove this also works by using an x-axis parallel to the ground rather than parallel to the incline. I understand how to get tan(θ) using the incline as the x-axis, but I don't...

Homework Statement At a construction side, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails, weight 10 kg and 20 kg, respectively, and are the same size. Diagram...

Homework Statement This problem was originally posted on Physics Problems Q&A: http://physics.qandaexchange.com/?qa=616/friction-between-two-disks Homework Equations Second Newton's law for rotation: $$\tau = I \alpha = RF$$ The Attempt at a Solution I tried to solve this problem as...

Consider a massless string which can rotate about a fixed pulley (first picture). The coefficient of static friction is μ. Assuming that the motion is impending, the goal is to find the equation that describes the variation in tension of the string. ( T2/T1 = eμΦ where Φ is the subtended angle.)...

This Wolfram Alpha Page contains a derivation of the parametric form of the brachistochrone curve that result from either assuming friction or its absence. I am asking for help understanding how the solution to the differential equation obtained from applying the Euler-Lagrange equation to the...

The problem is asking me to find the final speed of a 1100 kg car traveling at 24 m/s through 18m of mud, where the resistive force on the car is 17000 N. I don't actually know how to go about doing this, so any pointers in the right direction would be super helpful.

Homework Statement What minimum time is required to move a weight of mass 50 kg over a distance of 10 meters along a horizontal floor if the rope used to pull it breaks when the tension exceeds 20kgf, while a force of 10kgf is sufficient to start the weight moving or move it uniformly...

When we say the work done against friction, what do we mean by that? This concept is really worrying me.Thanks in advance!

A friend of mine and I have been discussing how to apply the first law of thermodynamics to analyze the quasi static expansion of an ideal gas in a cylinder featuring a piston having both mass and friction (with the cylinder). We have identified two different systems that can be used in the...

Homework Statement Two identical masses are connected with a rope and are gliding without any friction. Situation given in the picture: Determine after which distance "s" they stop if we have s=0 at t=0 with starting velocity ##v_0## Given: ##\alpha## and ##\beta## with ##\alpha < \beta##...

Homework Statement We have a yo-yo and the force ##F## which is the tension in the string and this is at the top tangent as shown in the figure attached with this problem. I want to figure out the direction of the friction at the point of contact. Homework Equations Newton's laws of motion...

I'm trying to determine the work done by a person as they pull a luggage up a ramp. The ramp has a height of 5 m and the distance the person walks up is 20 m. The weight of the bag is also 10 kg. I am trying to compare the work done by pulling the luggage up a ramp to carrying an equally heavy...

I learned this in college too. I once know the name of these zero friction piston rings but I have forgot. If I knew the name I could do Google search and learn more about them. College professor said, grooves are .020" wide and .020" deep. Pressure drop across the grooves make them act like...