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Questions tagged [friction]

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

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Does static friction only depend on the forces acting on the axis perpedicular to the plane where an object is located?

Suppose I have a vehicle with 4 wheels all connected to motors which is hauling a set of wagons. Suppose also that: The contact between wheels and ground plane is uniform. The weight of each wehicle ...
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Reason for neglecting frictional force in a particular type of Motion

A thin inelastic string is tightly wound on a cylinder. One of the ends of the string is attached to the above surface. Initially the whole system (string +cylinder) is held near the surface. When it ...
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Couple or torque

In the solution of Problem 527, over here, A homogeneous cylinder 3 m in diameter and weighing 30 kN is resting on two inclined planes as shown in Fig. P-527. If the angle of friction is 15° for ...
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Sliding to Rolling

In a problem where a sphere is initially sliding and then begins to roll after having travelled some distance. The thing that confused me is that the work done by friction on the sphere is not simply ...
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Does ABS increase the breaking distance of a car? [on hold]

Question: Can an ABS (Anti-lock Braking System) instead of decreasing the breaking distance actually increase it? If yes, is this its general behaviour, or only in specific circumstances? Wikipedia ...
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Physics with trigonometry homework questions? [on hold]

4) Two cars approach a snow covered (frictionless) intersection. Car A has mass Ma = 1800 kg, and Va = 12î m/s. Car B has mass Mb = 1200 kg, and Vb = 15j m/s. a) what is the total initial momentum, ...
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Magnetic force on an object

If I have an object moving through a magnetic field gradient of increasing strength, at any point along the gradient, what is the marginal field strength relative to the previous point required to ...
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How would the skidding distance change if the initial speed of the car were doubled? [closed]

A car with a mass of 800 kg is traveling with an initial speed of 10 m/s. When the brakes of the car are applied, the car starts to skid, and it experiences a frictional force with mu=0.1
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lateral forces acting on a stable vs unstable ladder [closed]

It's been several summers since my Physics O'Level, and my recall is failing. Please could anybody do me a quick summary of the lateral forces acting on a man up a ladder, both in its stable state, ...
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A 25-kg box is pulled to the right on a rough, horizontal surface with a rope that makes an angle of 40 [closed]

(a) Draw a good FBD for the box. (b) What is the apparent weight of the box? (c) What is the magnitude of the friction force acting on the box? (d) What is the acceleration of the box?
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Why don't brake rotors self level through use? [migrated]

A few months ago my brakes developed a wobble, and the mechanic explained that there is a high spot in the rotor so when I'm braking the brake pads grab that spot more than the rest and it makes the ...
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Force of friction between spinning cylinder and two perpendicular surfaces [closed]

There is a spinning cylinder in a 'corner' with radius R, mass m and friction koefficient k. I want to calculate both forces of friction ($F_1$ - wall and $F_2$ - floor).
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Tire pressure physics

I understand that with less tire pressure you get more surface area on the pavement and more friction which gives more rolling resistance, but does having less air mean that there’s more weight per ...
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Deriving equations of motion using Lagrangian formalism for inverted pendulum on a cart with friction between pendulum and pin

I know this is a problem with plenty of examples and solutions but I can't find one where the friction between pendulum and pin (I know it's negligible) is taken into account. My main question is if ...
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Equation of motion for compressible fluid

I am looking for simple mathematical model for transient flow that consider friction. Is it possible to modify Joukowsky’s equation in order to consider friction? that; $$ \Delta H - \frac{\Delta P_\...
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Rotating object on table: from sliding to rolling

A object which is rotating around a horizontal axis is placed on a surface, and starts sliding (with kinetic friction). After some time, it starts rolling without sliding through the table. The goal ...
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Work done by non-conservative force like friction

I have two questions: Q1 Why is work done by friction path dependent? Let us say that there are two points A and B that are vertically at a distance 'd' apart from each other. If I take an object ...
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Can I know if an object will slip or will accelerate forward when it is pushed by a force that exceeds the maximum force of static friction?

If we push a trash can, it will not move until we exceed the maximum force of static friction, but when we exceed the maximum force of friction, will the can slip or accelerate forward?
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Where to kick a ball to achieve rolling during the whole motion?

That's all the information I've got, so I don't really know what to do. But this is my idea: The equations of the motion are $$ma=F_0\delta(t)-F_{friction}$$ and $$\frac{2mR^2}{5} \frac{d \alpha}{d t}=...
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Force required to drive an electric vehicle

I am looking for the equation to calculate the energy required to move an electric vehicle of simply design based on rolling resistance, weight, wheel radius and air friction. The idea is to build a ...
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What force causes tangential acceleration? [closed]

I believe the static friction is responsible for the centripetal acceleration whereas kinetic friction is responsible for the tangential acceleration. But the answer key states otherwise and says it's ...
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Easiest Way to understanding coefficient of friction? [closed]

So I am having issues understanding how to find the coefficient of friction, I should have understood this couple chapters ago but I couldn't. I am not understanding the difference between the static ...
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Who is credited with the discovery of rolling friction? [closed]

Which physicians discovered and/or contributed at large to what we know of rolling friction today, and what exactly did they contribute?
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Work done on Earth by car

Whenever a car accelerates, friction is pushing it forward. However, because the contact point doesn’t move relative to the earth, friction does no work. By conservation of angular momentum, the ...
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How does pulling or pushing a heavy object resting on a wheeled platform affect the platform's motion?

If I am standing on a large wheeled platform at rest, perhaps reminiscent of a very large skateboard, and there is also a large heavy box on it and I start pulling the box with a rope toward me, then ...
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Can we estimate the coefficient of friction between two objects/materials?

I remember reading that it was impossible to theoretically estimate the coefficient of friction between materials even if their structure was known. The book where I've read this was The Feynman ...
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Conservation of Momentum and Friction in an Inertial Frame

Let us suppose that a rectangular, tabular body is moving in translational motion through space at a constant velocity and the surface of it has a low coefficient of static and kinetic friction. ...
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Is kinetic friction still constant at the transition from static to kinetic friction?

I'm looking at this graph from here: The answer providing the above graph explains how kinetic friction is constant. However, the graph tells me that after static friction is overcome, there is a ...
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Effect of velocity upon kinetic friction

This question has been asked before... (Does the force of kinetic friction increase with the relative speed of the objects involved? If not, why not?), ...but there's a very specific part I'm ...
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Pure rolling and friction

If I launch a rigid cylinder (or sphere, etc.) to the surface which has a coefficient of kinetic friction and static friction with initial velocity $v$, I think it will decelerate rotate (with ...
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Adhesion vs Static Friction

I feel like this question should have a simple answer, but I haven't been able to find one anywhere. I hope someone can help: In short, my question is why the force of static friction is so much ...
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Can a pair of frictional force have positive work?

My teacher told me that friction can have positive work which is true. But he told that a pair of friction forces can never have positive work. I am not able to think the reason for this statement. ...
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Is it possible to have a coefficent of friction of zero?

I know that friction is determined by the equation $$F_f = \mu_fF_n ,$$ so technically if the normal force is $0$ then the force of friction will also be zero, but my question here is whether or not ...
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How is damping force related to frictional force?

I have a problem and I want to determine the friction coefficient using diffential equations i.e. solving the equation (this is from a Under-damped Oscillator) $$ m\ddot x+c\dot x+kx=0. $$ Suppose I ...
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Friction and Work in Inertial Reference Frames [duplicate]

Say a train is moving in the positive $x$-direction at 100 meters per second with respect to the ground frame. Now let's say someone is pushing a large box in one of the cars of that train in the ...
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Predicting Rotation vs Sliding Forwards when Pushing an Object

Suppose there is a cuboid object sitting on a table, and a force is then applied to it. This figure shows the top-down view: I am curious to understand how the object will move due to this force, ...
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How can the friction force equals to the net force in this momentum question?

Question- from https://www.physicsclassroom.com/calcpad/momentum/prob29.cfm A physics student hurls a $315-g$ ball directly into a $3.54-kg$ box which is at rest on a table top. The baseball strikes ...
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Confusion about conservation of linear momentum in a bike

A bike is moving with some velocity.There is some frictional force between the wheels of bike and ground.Now you apply brakes and the bike stops after some time.Brakes apply a force say F on wheels ...
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Is there any situation when oil increases friction?

I have read everywhere and tried myself to experience oil smoothening surface interfaces, thereby reducing friction. I was curious if there are instances where oil increases the friction between those ...
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If you set crates of different masses to the same initial velocity, which one will stop first and which one will have the greater displacement? [closed]

If you set two crates of different masses to the same initial velocity, which one will take the longest amount of time to come to a stop? Which one will travel the longest distance? Which one will ...
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Why do bikes hardly ever skid while braking with the front wheel?

When abruptly braking with the rear wheel on a bike, it tends to skid pretty easily. Doing the same with the front wheel is a very different experience. Instead of skidding, the bike lifts the rear ...
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How much clamping pressure would it take to hold up the weight of a human?

I don't know anything about physics. This question comes from an argument I had with a friend. Basically my question is this: Is it possible for a human to hold themselves up only by clamping their ...
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Mathematical Mechanics - Friction Question (weight is laid upon an inclined plane)

A weight W is laid upon a rough plane [µ=1/(sqrrt3)] inclined at 45 degrees to the horizon. It is connected by a string passing through a smooth ring A, at the top of the plane, with a weight P ...
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How can static friction depend on the normal force, but be directed orthogonal to it?

According to my understanding: two orthogonal forces aren't related and two orthogonal vectors don't affect each other the force of static friction $F_s$ depends on the normal force $F_n$, so $$F_s = ...
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Does static friction apply when an object stops for a very small amount of time?

It is my understanding that static friction between two surfaces arises at least partly due to inter-molecular forces, e.g. Van der Vaals forces. The question: Consider this scenario: If I push a box,...
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Sharpening Scissors with aluminium foil

There are lots of websites 1, 2,3 that claim you can sharpen scissors by cutting aluminium foil. Does this work? What would be the cause of this?
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Rolling friction - neglection of reaction force on the opposite side

This is a picture taken from wikipedia. Here the rolling friction is explained. W is the weight, F is the driving force( neglecting friction in the bearing etc,) r is the radius of the wheel, R is ...
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What is the reaction force if i push my leg downward in deep space or on a friction less surface? [closed]

As per newtons law,for every action there is an equal and opposite reaction. Consider first situation,if i exert a force on a friction less surface,what is the reaction force? What will be the ...
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The radius of a body in circular motion

If the kinetic energy of an object in circular motion due to a gravitational force is given by: $$E_{kinetic} = \frac{GM_{object}M_{planet}}{2X_{radius}},$$ then why does radius decrease when ...
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Is the mechanical power output of a car constant?

According to my textbook. The mechanical power output of a car is constant. My reasoning tells me otherwise though. According to a lot of pages on this forum related to the driving force of a car. ...