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

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302 views

Does drag produce heat?

When a solid object moves through a fluid drag is produced. Does this drag produce heat? I believe drag should produce heat as it is the friction between fluid and surface of object. Is this true or ...
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2answers
778 views

Consider a horizontal surface with or without friction. Ideally, will a wheel rolling without slipping roll forever in both cases?

Suppose a wheel is rolling smoothly on a horizontal plane i.e., it is rolling without slipping. Now let's take the two cases of the horizontal plane: It has friction It is frictionless In the ...
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1answer
302 views

Calculating the path of a ball with spin moving across a table

A ping pong ball is rolling over a smooth (but not frictionless) table. During its travel, a clockwise spin is placed on the ball. The ball's path is changed to move to the right (in perspective from ...
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2answers
20k views

Does kinetic friction increase as speed increases? [duplicate]

Possible Duplicate: Does the force of kinetic friction increase with the relative speed of the objects involved? If not, why not? Layman alert...I last did physics in high school, and am just ...
3
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1answer
684 views

What is the function of the top point of a bouncing ball?

A ball is thrown away as parallel to x axis from M(0,h) point with speed V . After each jumping on x axis , it can reach half of previous height as shown in the figure.(Assume that no any air ...
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3answers
116 views

Is static friction the only force causing a car to move (without sliding)?

A car is moving without sliding means that the friction between wheels and the ground is static friction. This is the force causing an object to move forward, therefore, its direction is the same as ...
3
votes
2answers
139 views

What is the minimum force required to move this block

Please don't report. It's not a homework question. Yesterday on my physics test there was this question. there is a block of mass $m$ connected to a spring as shown in the figure. the spring constant ...
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2answers
100 views

Dissipative forces and reversible processes

A book that I have contains the following lines: For a process to be reversible, the dissipative forces such as viscosity and friction should be absent. My question is why?
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2answers
378 views

What is a self adjusting force?

What is a self adjusting force? I searched it everywhere on internet but not got my answer and I have no other source to get its answer except this site so please help me.
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1answer
41 views

Everyday Low-Energy Atom Collider

During the shearing of metal in a machining process, what exactly is the source of the heat that is produced? I realize that the energy is coming from the work being done by the cutting tool. I am ...
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1answer
130 views

Could $\int (\ddot\phi + \mu\dot\phi^2)d\phi$ ever be negative? How to show it?

I am working on the following problem: Given a mass $m$ at rest at the base of an incline surface shaped like 1/12th of a circle with radius $R$. The mass is pulled up the incline by a rope that ...
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2answers
2k views

A block on a wedge

The system is as follows - Friction exists only between the 2 blocks. I am trying to find out the accelerations of $m_1$ and $m_2$. Let $a_2$ be acceleration of $m_2$, and $a_x$ and $a_y$ be the ...
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5answers
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Finding the force of friction of a moving object and its change when it accelerates to a constant speed

I have been searching for a straight forward answer to this question for ages now and it is driving me crazy. Here is what I know: If an object is moving at a constant speed the force of friction ...
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2answers
2k views

Conservation of angular momentum in helicopter

I have a small RC-controlled toy helicopter with removable tail rotor. Suppose I remove the tail rotor, hold the tail with my hand, start the rotor until it moves with constant angular velocity and ...
3
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2answers
656 views

Strict general mathematical definition of drag

Is there a formal definition of drag, say, as some surface integral of normal and shear forces? There seem to be a lot of formulas for specific cases, but is there a general one? I need to accurately ...
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2answers
69 views

Pulley rotation

In the given arrangement, the friction in between the string and the pulley is enough to avoid slipping and the string is light. On the basis of these assumptions, would the tension in the upper part ...
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4answers
559 views

Would this box on the floor rotate based on friction?

There is a floor that friction is proportional to its velocity (like $F=-kv$) and there is a box with its width as $l$ and its height as $h$. (you may assume that $l$ is longer than $h$). It is on the ...
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4answers
769 views

Ball rolling into a bowl - where is its maximum KE (speed)… given there is friction. See diagram

Please examine this diagram and answer the apparently trivial questions. I am particularly interested in reasoned answers for part (a)(ii) - where is the maximum Kinetic energy? I say it is at B (...
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2answers
173 views

Friction on roads

I have a question with which I am having trouble. A 71m radius curve is banked for a design speed of 91km/h. Given a coefficient of static friction of 0.32, what is the range of speeds in which a car ...
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2answers
456 views

Does air resistance ever slow a particle down to zero velocity?

If a particle moves in a place with air resistance (but no other forces), will it ever reach a zero velocity in finite time? The air resistance is proportional to some power of velocity - $v^\alpha$, ...
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1answer
1k views

Rope wrapped around a cylinder

If a rope is wrapped aound a cylinder what is the relationship between the amount of wrap and the ability to resist slipping off of the cylinder? An example would be if I had a 180 degree wrap and ...
3
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0answers
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 ...
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3answers
83 views

When only part of the surface an object is in contact with has friction, what is the normal force I should use?

I have the following exercise: A uniform rod of mass $M$ is given a horizontal velocity $v$ on a rough track as shown in the figure. The surface is rough on the right side of the origin $O$ and ...
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2answers
131 views

Effect of friction on a moving body under a variable force

Given the system in the figure: The block slides on a horizontal surface and is acted upon by a force $P$ which varies in magnitude as shown. Knowing that the coefficients of friction between the ...
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0answers
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 ...
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0answers
47 views

Friction in Lagrangian Method [duplicate]

A uniform, flexible chain of length $l$, mass $m$, hangs off a frictionless table-top of height greater than $l$. The length of the part of rope hanging off is $x$. Gravity accelerates the part of the ...
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1answer
622 views

Rolling a ball into a cone; what should the forces overall be?

This is my solution to finding angular displacement/velocity/acceleration on cone so far. Consider a cone, with an apex of half-angle $\psi$ pointing down, and a height of $h$. If I roll a ball into ...
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0answers
197 views

How much weight is lifted from each side? [closed]

I don't know the math to do this, so I am asking here if someone can work this out with all of the details I'm providing. Total mass EST.: 2,400 lbs. Length from front to back: 14 feet 6 inches. ...
3
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1answer
269 views

Heuristic equation for Friction force between materials

I'm programming a game where different types of objects will be sliding over different types of terrains (Top-down in two dimensions). At my current level of physics education we are given the ...
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3answers
285 views

Sliding ruler on table top

I've got a standard foot-long flat plastic ruler (about an inch wide) and a desk with a smooth formica-like surface. When idly passing time reading on the computer, I will pick up one side of the ...
3
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1answer
166 views

Is it possible to eliminate Van der Waals interactions?

I came to know that the friction force actually depends on the surface contact area due to weak interactions (adhesion due to Van der Waals forces) between the atoms of both materials increasing in ...
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votes
2answers
470 views

Aircraft - static take off - how is this possible?

From this Aviation SE answer, and personal experience, aircraft routinely are held on their brakes while the engines are run up to full power, prior to take-off. Intuitively, to me at least, this is ...
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2answers
239 views

Why do racing tires (slicks) provide more traction with the road?

Google: By eliminating any grooves cut into the tread, such tires provide the largest possible contact patch to the road, and maximize traction for any given tire dimension. My understanding is that ...
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3answers
3k views

Why is using Newton's First Law failing me?

A factory worker pushes a 29.7kg crate a distance of 5.0m along a level floor at constant velocity by pushing downward at an angle of 32$^\circ$ below the horizontal. The coefficient of kinetic ...
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4answers
68 views

What makes the magnitude of the force of friction velocity dependent in one scenario, but not the other?

When a solid objects makes contact with another solid object, I believe the magnitude of the force of friction between them does not depend on the relative speed of the two objects. When a solid and a ...
2
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3answers
423 views

Time reversal symmetry in the presence of friction

I was reading a paper on time reversal symmetry, and came across an example of a pendulum swinging in the presence of friction: When we consider the more realistic physical situation of a swinging ...
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2answers
2k views

Angular momentum conservation while internal frictional torque is present

So this appears in a problem which looks simple enough in its context; It's something like this: Two discs, A and B, are mounted coaxially on a vertical axle. The discs have moments of inertia $I$ ...
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4answers
8k views

Maximum acceleration for wheel-driven vehicle from standstill

Once I discussed cars and there was a question about rate at which the car gains its speed ($100\:\mathrm{km/h}$) from standstill (i.e. acceleration). At some point of conversation it came up that ...
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3answers
2k views

Why does soap make shaving with razor less painful?

The lubricant is needed only on the hair surface? How can the blade cut the slippery surface? Why does soap make shaving with razor less painful?
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2answers
51 views

What orientation will let me drive the fastest with a tray of coffee on the floor? [closed]

I like coffee. I like to drive fast. These two don't usually go together, unless you like that coffee all over your floor because you tipped it over going around the corner. If I have up to four cups ...
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4answers
1k views

Does stopping the same bike and rider at the same velocity with the front brake require less energy than the back brake?

It's the same body made by the rider and the bike moving at the same speed. So, even though braking on the front/back alters the normal forces on the opposite wheels thus creating more friction with ...
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4answers
302 views

Turning on a straight, unbanked, frictionless road

I was learning about circular motion when this question struck me: In real life situations we are able to take a turn along a circular arc with our bike because friction provides us the necessary ...
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3answers
3k views

Is friction a product of Newton's third law?

Newton's third law is defined as $F_{12} = -F_{21}$ Is friction a product of this law? For example, if I take my hand and slide it across the floor in the $+x$ direction... My hand exerts a force $...
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2answers
670 views

About vector form of friction

I read a text on mechanics and in the chapter on friction, there written that the kinetic friction is in the form $$f_k = \mu_k F_N$$ where $f_k$ is the kinetic friction, $\mu_k$ is the kinetic ...
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1answer
2k views

Direction of friction on particle placed on a rotating turntable

If a particle is placed on a rotating turntable then the particle has a tendency to slip tangentially with respect to the underneath surface... So the friction should act tangentially to the particle.....
2
votes
2answers
113 views

Center of mass chaotic in n-body gravitational interactions?

I wrote a gravitational particle simulation. To prevent the particles flinging off out of the screen, I added a bit of friction (it also makes the animation prettier as particles spiral into one ...
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2answers
327 views

Work done by frictional force on a sliding block

A block slides across a table horizontally with an initial velocity $V$. The frictional force $F$ brings it to rest after its Centre of Mass covers distance $S$. What is the work done by the ...
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1answer
150 views

Rolling w/o slipping - does a friction force acts in this scenario?

Assume the following scenario of rolling without slipping: A small disk starts rolling w/o slipping at $\vec{r}_{CM}=-9R\hat{x}$ (scenario A) and reaches the bottom of the large hollow disk (...
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1answer
621 views

Why do bowlers rub the ball before bowling in a cricket match?

Why do bowlers rub the ball before bowling in a cricket match? What is the science behind it? Is it because of friction?
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1answer
2k views

How do I account for the direction of friction acting on a spring?

I would like to set up the equations of motion for a simple spring oscillator. Let's have a spring lying horizontally; we attach a small mass $m$ to the (massless) spring. The force of the spring ...