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Questions tagged [friction]

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

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An easy dinamic problmem [on hold]

On a ladder of l=6m placed at the height of h=4.8m and with the mass of 50kg there is a man of mass 80kg at the point 0 in the mid of the ladder (l/2) and the point c where the gravity of the ladder ...
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2answers
36 views

Does this graph represents only the magnitude of the friction force?

Friction force acts in the direction opposite to the relative motion between surfaces. For example, when a block is attempted to move from left to right with a force $F$, there will be an opposing ...
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1answer
42 views

how does a car move? and how do the brakes affect its velocity? [duplicate]

im doing a project that requires me to understand how cars move. from what I understand , its the friction that is creates in the tires that enables the tire to rotate, which then push the car forward....
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1answer
37 views

A circular motion problem [on hold]

A car goes on a horizontal circular road of radius $R$, the speed increasing at a constant rate $\frac{dv}{dt}=a(constant)$. The friction coefficient of the tyre is $\mu$. Find the speed at which the ...
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1answer
21 views

Is friction enabling relative motion between bodies in contact?

If the surface object B is placed on is frictionless, on applying a force F on object A, friction will act on object A opposite to the direction of the force applied (opposite to the direction of its ...
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1answer
52 views

Explain why the magnets move towards eachother in this setup

I have two bar magnets (actually stacks of small magnets, but I believe they should behave the same) attached to a stack of (presumably conductive) coins, and not diametrically opposite. When I ...
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0answers
22 views

Explain why the angle of incline of the ramp affects friction between the surface of the ramp and the object [on hold]

Experiment: the object is placed on the ramp and the angle between the ramp and the floor is changed.Explain why the angle of incline of the ramp affects friction between the surface of the ramp and ...
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1answer
31 views

Centripetal Force Static Friction

I understand that when a car is turning, it is using static friction to do so. The wheel is turned where the perpendicular component of the wheel is opposing the direction of motion, creating a force ...
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0answers
59 views

At what speed in air would a solid object turn to plasma?

Just curious, friction can heat up what ever is moving. The faster something moves the quicker it heats up. Is it possible in the perfect scenario to turn a speeding solid object to plasma through ...
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0answers
46 views

How to calculate the viscous damping coefficient of a spherical viscous medium enclosed by a spherical solid medium?

In this article by Rahn and Barba, a flat-spin transition manoeuvre is investigated. For this it is assumed that a rigid spacecraft contains a spherical, dissipative fuel slug of inertia $\boldsymbol{...
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1answer
27 views

Oscillating Bar on rollers [closed]

I'm currently preparing for my exam and am stuck at the following scenario. Suppose we have two rollers rotations against each other and now place a bar on top. The distance between the rollers is $L$...
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1answer
30 views

Force Required To Move A Wheel

Consider a wheel upright like this: Is the force required to move the wheel by pushing it in the direction that its tire is facing the same magnitude as the force required to move it by pushing at ...
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2answers
30 views

Free body diagram for a non-fixed (movable) ramp, with a box at rest on top of it

I'm having trouble figuring out how this free body diagram would look. The question involves a block at rest on a ramp, which is in turn at rest on a table. All objects are made of the same material, ...
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0answers
40 views

A block and cylinder bodies on a rough inclined plane [closed]

On a rough inclined plane of inclination 45° a block of mass m and a cylinder of mass 2 m are released Coefficient of friction between all the surfaces of contact is 0.5. If the acceleration of the ...
1
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3answers
71 views

Normal reactions with moments

A uniform ladder, $AB$, is leaning against a smooth vertical wall on rough horizontal ground at an angle of $70°$ to the horizontal. The ladder has length $8\ \rm m$, and is held in equilibrium by a ...
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3answers
39 views

Friction on car tires

In tipler and mosca 5th edition the following passage occurs: I am a bit confused by the sentence starting "If the power delivered by the engine is small enough...". I am not seeing why the power ...
0
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1answer
39 views

Billiard ball with side spin

A cue ball is travelling along a snooker table. Initially, it has only side spin (yaw). As it travels it will develop a rolling spin (pitch). Can the ball develop any (roll) and thus move off the ...
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0answers
26 views

How to calculate coefficient of friction of given surface?

I have a surface in real life whose coefficient of kinetic friction I need to calculate. I've seen a method where people attempt to measure the angle at which the object on top begins to slide off the ...
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1answer
25 views

Static equilibrium (possibility)

In static equilibrium for a ladder leaning against the wall it is supposed to rotate about a point. Why we are not assuming it to slide down as in our practical life?
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1answer
46 views

Sign of the work done by dissipation forces

I don't understand this passage from the book I'm reading: Physically, it is clear that a system cannot be conservative if friction or other dissipation forces are present, because $\mathbf{F}\...
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1answer
11 views

Does Horizontal Velocity remain constant when it hits a surface in a Parabolic Motion?

It is told in one of the answers that the horizontal velocity stays at 4.0 m/s after the ball bounces from the plate. Why is it still at 4.0m/s, isn't there friction or is it neglected for the sake ...
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0answers
36 views

Calculating the Slip Ratio of a Vehicle Tire

I am trying to create a simulation to simulate a vehicle's tire using Pacejka's Magic Formula. From what I understand, the formula calculates the longitudinal force that the tire will experience using ...
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1answer
35 views

Finding the accelerations of objects [closed]

I want to know how to get the accelerations separately in each object
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0answers
35 views

Work done by frictional force when rolling without slipping [duplicate]

When an object is rolling (no slipping) on a slope there should be a frictional force which causes rotation. But when we use power insulation philosophy, we haven't considered about an energy loss ...
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1answer
23 views

Incline plane question with both static and kinetic friction [closed]

A box of mass m = 2.5 kg is released from rest near the top of the incline. The angle of the incline is 35 degrees above the horizontal. The coefficients of static and kinetic friction between the box ...
1
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1answer
35 views

No friction in pure rolling - how about driving a car?

I remember the un-intuitive result that pure rolling without acceleration involves no friction by the law of conservation of angular momentum. Conjectures: I understand that when I'm driving a car at ...
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4answers
90 views

Principle of friction force

When two equal and opposite forces act on a body at rest or in motion we say it is rest or in its state of motion. But when a body kept on a table starts moving uniformly due to a force applied, it ...
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2answers
56 views

What force is acting on a car?

We say acceleration is produced in a body when a force acts on it in some direction.When a car moves with acceleration and I'm an observer on ground.What force should I say is acting on the car?
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1answer
40 views

Why the capstan equation is exponential? [closed]

Does anybody knows any intuitive explanation about the reason that the capstan equation is exponential and not, as expected, linear?
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1answer
62 views

Does a velocity perpendicular to the gravitational force affect frictional force? [closed]

A motorcycle rides on the vertical walls around the perimeter of a large circular room. The friction coefficient between the motorcycle tires and the walls is μ. How does the minimum μ needed to ...
0
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0answers
16 views

What is the internal force at the end of a tire and relation to the torque?

If an car axle is subject to a torque and if I consider the contact point of the tyre to the ground, it is stationary. Assume the car is moving left to right. Would the contact point be subject to an ...
6
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3answers
92 views

Why do office chairs rotate when pushed/pulled out?

A common source of frustration when I'm at work is the fact that my rolling office chair's wheels rotate whenever I push it forward or backward from my desk, which can cause it to bump my computer ...
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2answers
57 views

what are the sources of energy loss for a ball rolling down slope?

I am experimenting in lab with an iron sphere rolling down a smooth aluminum ramp. The final velocity is smaller than the one predicted assuming energy conservation (see calculations below), which ...
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2answers
51 views

Why is the work done by friction zero when body is rolling? [duplicate]

Why is the work done by friction zero when body is rolling? Does it mean no energy is dissipated by friction.
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3answers
54 views

Is vector sum of momentum constant if there is friction?

In a head-on collision of 2 objects with the same mass and speed in opposite directions, the vector sum of momenta before and after the collision stays the same and is equal to zero. I've read that if ...
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2answers
37 views

Real Pulley and Newton's Third Law

In a real pulley with two masses hanging from either side, the pulley rotates due to a non-zero torque, which I understand is caused by friction on the rope. I understand that if each mass was ...
2
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3answers
104 views

Why does friction not accelerate a wheel?

It seems like a silly question because this defies common sense, but it appears that friction is supposed to accelerate a wheel (not attached to anything). We can derive from Newton's laws that $\...
0
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1answer
31 views

maximal acceleration of a wheel-driven vehicle

I was thinking about the maximal acceleration of a bicycle, I found a similar question. What remains unclear is that I found two coefficients of friction, one for rolling and one for static friction. ...
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2answers
86 views

Will a wheel keep rolling in perfect vacuum? [duplicate]

I have a query which I cannot resolve by finding enough arguments. A perfectly round wheel that also doesn't have any contractions due to gravity is placed in a perfect vacuum, so no drag is present. ...
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4answers
65 views

Work when there is more than 1 force

I know that for an object with an applied force, the work done is $$W = Fd \cos \theta.$$ I was wondering what would happen when there is another force (e.g. friction)? Is it better to say that the ...
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2answers
47 views

Why does less friction in a wheel result in more speed? [duplicate]

Everyone knows that racing bikes have narrower wheels and that, by definition, friction reduces speed. What I don't understand is that since at no time is the wheel of the bike in horizontal motion ...
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4answers
57 views

Car flip in crash while dragging

In some movies (Cars2), a driver would take a sharp turn while dragging the car and it would launch in air and flip. Can this happen in real life? If yes then what is the physics behind it? Only ...
10
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5answers
2k views

How can friction do no work in case of pure rolling?

I have read various answers , on PSE and elsewhere , and most of them explain that the point of contact of the rolling object undergoes 0 instantaneous displacement in the direction of friction, I ...
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2answers
28 views

Do you have an idea for two easy experiments to measure the coefficients of static and sliding friction of a rope wrapped around a steel rod?

I'm researching a phenomenon dependent on the Capstan/Euler-Eytelwein-Equation. To model a simulation, I need the friction coefficients. I came up with the idea of hanging one mass $m_1$ on one side ...
4
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2answers
127 views

What opposes a smooth motion of a rubber eraser on a glass surface?

A metal block smoothly moves on a glass surface. But a rubber eraser doesn't move very smoothly on a glass surface. In each of the cases, the surfaces are smooth at the macroscopic scale. If the ...
4
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2answers
69 views

Do I force the intercept to zero when determining the coefficient of friction?

I have made these measurements of kinetic friction force vs normal force: I want to measure the coefficient of friction as the slope of the line. Unfortunately the line does not pass through $(0,0)$. ...
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2answers
68 views

What is the justification for going from $\frac{d(v^2)}{dt}dt$ to $d(v^2)$ in this derivation regarding work in the presence of kinetic friction?

I do not understand what is being done in the last line of the quote, where we manipulate one integral to get another. Incorporating Newton's second law $\Sigma\mathbf{\vec{F}}=m\mathbf{\vec{a}}$ ...
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0answers
25 views

fluid flow over a incline and decline slope

I was recently watching fluid flow simulations on a cone. And noticed that if the tip on the cone is facing in the opposite direction to the fluid flow i.e fluid flow in $+x$ and tip of cone in $-x$ ...
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5answers
580 views

Does rolling friction increase speed of a wheel?

I know there are a lot of questions about rolling friction, but I couldn't find any that addressed my specific problem. Note the following picture where the wheel rotates clockwise. The rolling ...
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1answer
23 views

Friction Behavior at corners

The question: Find the range of value of $L/D$ such that the system remains in static equilibrium. And explain why such a range exists and not just a single value. This is the question where I ...