# Questions tagged [friction]

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

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### 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 ...
3answers
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### 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 ...
1answer
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### 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 ...
0answers
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### 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 ...
1answer
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### 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?
3answers
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### Can we know when rolling occurs without slipping?

In school we solve a lot of physics problems involving rolling cylinders/hoops/wheels. Often it is specified in the question statement that "rolling can be assumed to occur without slipping". Then we ...
1answer
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### 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. ...
2answers
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### 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. ...
4answers
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### 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 ...
2answers
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### 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 ...
4answers
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### 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 ...
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 ...
2answers
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### 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 ...
2answers
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### 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 ...
2answers
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### 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 $(0,0)$. ...
2answers
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### 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 $\Sigma\mathbf{\vec{F}}=m\mathbf{\vec{a}}$ ...
0answers
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### 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 $-x$ ...
6answers
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### 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 ...
1answer
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### 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 ...
3answers
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### Will making the surfaces extra smooth increase friction?

If we make the surfaces enough smooth that all asperities are removed then the two bodies in contact may act like a single body making frictional force infinte. I know this is practically impossible ...
0answers
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### How to calculate drag caused by string?

An example - I throw a tennis ball with a short string hanging off one side. As the ball flies the string is dragged to the side opposite the direction of the ball's velocity vector, anchoring the ...
1answer
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### Why friction causes energy to be lost in terms of heat when it appears to be an energy transfer mechanicsm?

For example, when we move/walk, we apply a force (via friction) on earth, and the earth in turn on us. So essentially I see it as an energy transfer as follows: Suppose I move in same direction as ...
1answer
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### Why is the friction force on the bed opposite of the gravity [closed]

So here is a simple problem and here is a diagram that I find found online. Why is the frictional force pointing downwards. I mean I get the correct answer if I follow this diagram and math checks out ...
1answer
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### Direction of friction in non-inertial reference frame? [closed]

A beetle is moving radially with velocity $\bf{v}$ on a disk rotating with angular velocity $\bf{w}$. The coefficient of friction between the beetle and the disk is $\mu$. Find the distance $x_0$ ...
1answer
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### Damped oscilliations on a ball rolling in a U-shape

How do you calculate the rate of loss of energy on a ball moving in a U-shape (half sphere)? Can I simply look at the height of the ball at its peaks and measure the difference between the potential ...
2answers
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### Static or Kinetic friction

When a body is acted by a force such that it begins to move. In that case which friction is applicable? Is it the static friction as that would give a minimum value of force required to move the body? ...
4answers
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### Friction acting as an internal force

I was solving this problem in my assignment: Assuming a frictional force F acts on the block of mass m, a force -F will act on plank of mass M. Hence, the net work done by frictional force should be ...
1answer
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### Does the mass affect the speed if friction is 0

A block $m_1$ strikes another stationary block $m_3$ inelastically . Another block $m_2$ is kept on $m_3$.Neglect the friction Between all contacting surfaces. Since $m_2$ is kept on $m_3$ and all the ...
2answers
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### Being Frictionless, surface of contact

I hear frequently references to a smooth surface, or frictionless pulley. Can being frictionless be obtained if only one of the 2 surfaces has 0 coefficient of friction? Or it is for the contact of ...
2answers
160 views

### Why does water take a “wet” path?

Allow me to explain what I mean... ((I am asking this question in the physics section in hopes of finding a "physics" argument)) I shall make it clear what I mean by demonstrating an experiment... ...
3answers
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### When does a wheel stop slipping?

I am learning about friction in rolling motion in my high school physics classes and I don't have much intuition about this. If a wheel is rolling and slipping there is a dynamic friction involved, so ...
2answers
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### Damped drive oscillating systems

I am currently looking at the theory of find the viscosity of and object through damped harmonic motion, and tho it can be done there is obviously a limitation with regrades to the medium. If the ...