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

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2answers
97 views

Does friction depend on the direction of motion?

In my experiment of finding the moment of inertia of a flywheel, I first rotate the flywheel in the anticlockwise direction and then in the clockwise direction, but I am getting different values of ...
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1answer
100 views

Intuition for why friction on rolling objects is in the same direction as motion?

When we usually draw friction, it is opposite the direction of motion. However, in rotational motion problem when a cylinder is rolling on the floor, it is in the same direction as the motion. I did ...
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1answer
33 views

treadmill physics, wheel size vs. counterforce

I'm trying to design a classical treadmill for rodents which has two wheels at the two end and a plain "conveyor" belt in between. What is the best way of designing this if i want to have minimal ...
1
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3answers
138 views

Force of an object “skidding”?

Let's say I put the brakes on really suddenly in a car that was moving at 40mph. If I know how much force it takes to break the adhesion of the wheels, how do I find the force the car is exerting? ...
1
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2answers
335 views

Why is kinetic friction less than static friction? [duplicate]

Ex: A wooden block is lying on a table. I am told that because the block is still, the microscopic surface irregularities form more complicated interlocking structures. Is it because the force of the ...
-4
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3answers
173 views

Gravitational Force [closed]

If energy is represented by Acceleration=A, then am=F ams=W (ams)/t=P Acceleration is always present when motion is present, acceleration is the energy. Since gravity translates into ...
2
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0answers
51 views

Why is the coefficient of kinetic friction greater than the coefficient of static friction? [duplicate]

I am a physics major taking freshman year physics courses. We did a lab experiment where we were given three objects and inclined plane, and we were asked to find the coefficients of kinetic and ...
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3answers
371 views

Acceleration of body rolling down inclined plane

Acceleration of a body rolling down an inclined plane is given by: $$\frac{g\sin\theta}{1+\frac{k^2}{r^2}}$$ $g$=acceleration due to gravity $\theta$=angle of inclined plane $k$=radius of gyration ...
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2answers
229 views

Can friction change the resonance frequency of a system?

I am simulating the transient response of a mass-spring-damping system with friction. The excitation is given in the form of a base acceleration. What I am not sure about is: can the friction change ...
1
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1answer
81 views

Work done by friction opposing a force at an angle

Let's imagine there's a block of mass m sitting on a rough surface with a kinetic friction coefficient $\mu$. It's being pulled with a constant force $A$ at $h$ degrees above the horizontal and is ...
1
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1answer
67 views

Physics of wheel slip?

I am trying to write a program that simulates the physics of a locomotive (diesel, not steam). I already have a method to get the tractive effort of the locomotive. If anyone must know, the one I am ...
1
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3answers
50 views

The formula for the kinetic friction on inclined surface

I'm confused about the formula for the force of friction on inclined surface. It says that $f$ (force of friction) = $\mu N$ (where $\mu$ is the coefficient of the friction). Is: $$f = ...
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0answers
18 views

In practical, how to find the friction of rubber vs plastic? [duplicate]

I did an experiment. The experiment was to use a gripper which had rubber fingers to grip a plastic rod which attached to a mass. After that I had a linear motor to move the gripper. What I wanted ...
1
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0answers
15 views

Sliding Wine Glass [duplicate]

Earlier today, I came across a strange phenomenon involving a just-washed wine glass and a countertop. The gist of it is: when you place a warm wine glass upside-down on the wet countertop, it starts ...
1
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2answers
52 views

Simultaneous: static friction and acceleration

I need help thinking about two events happening simultaneously. I have a heavy block on a surface with static and kinetic coefficients of friction, though they are unknown. The block is connected to ...
0
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1answer
38 views

Circular Motion and Simulated Gravity

People have proposed that a spinning cylindrical shape could be used to simulate gravity. Will gravity be simulated if the cylinder is frictionless? My brain can't seem to wrap around the idea that ...
2
votes
1answer
72 views

The role of mass in the tablecloth trick

Apologies if this has already been answered, but I have a question about the role of mass in the classic tablecloth trick, where the demonstrator pulls the tablecloth out from underneath a set of ...
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1answer
34 views

Using resultant vectors to calculate how long it takes to travel a distance [closed]

A box of books weighing $320 \;\mathrm{N}$ is shoved across the floor of an apartment by a force of $569 \;\mathrm{N}$ exerted downward at an angle of $36.5^\circ$ below the horizontal. The ...
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votes
5answers
1k views

Zero gravity means zero friction?

The frictional force acting on a body placed on a horizontal plane is $F=\mu{R}$ where $R$ is the normal reaction and is equal to weight of a body in this case. And $\mu$ is the coefficient of ...
1
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1answer
139 views

If a body slides down a frictionless inclined plane what will be the net normal force?

If a body(m) slides down a frictionless inclined plane (M), will the net normal force between the ground and the inclined plane be (M+m)g ? I feel it should be less than (M+m)g. This is because one ...
0
votes
1answer
31 views

How to develop the static and kinetic friction formula? [duplicate]

How do you end up with the formula for Amontons' first law of friction? ($F_s = \mu_s \times N$) or ($F_k = \mu_k \times N$). I know how to use the formula. Now I need to know how to get to it.
0
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2answers
49 views

Static vs. kinetic friction and the “normal-force” considered

Consider two cases. First, we have a box that a person applies a force to (say to the right). The force of friction (static) is then directed to the left. Second, say that the box is moving at ...
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4answers
143 views

Is cause of this equilibrium - tension or friction?

This is a very odd problem which I have. As you can see in the diagram, the string is taut. So, if there was no friction you could clearly say that tension is balancing it or if there was no tension ...
0
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2answers
57 views

Why does a block 2 on a oscillating block 1 start sliding at the maximum acceleration?

A block of mass $ m_{1} $ is oscillating horizontally with another block on it of mass $ m_{2} $. There's friction "k" between both blocks, so the thing is why the second mass starts sliding at the ...
2
votes
3answers
220 views

Terminal velocity and distance traveled with constant but limited power

I'm trying to model how far to move an object over time according to a power applied resisted by friction. So maybe... an object accelerates at a certain rate until the power provided can no longer ...
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4answers
59 views

Why consider only $x$ component of accelerating block pulled by cord at an angle?

A $5 \, \text{kg}$ block is pulled along a horizontal frictionless floor by a cord that exerts a force $F=12 \, \text{N}$ at an angle $\theta = 25 \, \text{deg}$ above horizontal. What is ...
3
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2answers
145 views

At what wind speed does wind chill's conductive cooling exactly cancel out the compressive heating of the air?

At relatively slow wind speeds such as 15mph, wind chill drains heat from an object as it flows past, and this conductive cooling effect seems to increase as the wind speed increases. However, at very ...
4
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1answer
66 views

What is the specific source(s) of sliding kinetic friction

In simplistic (K-8) physics classes, it seems to be generally instructed that the friction between two moving surfaces is due to the unevenness of each surface and the microscopic roughness. However, ...
0
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0answers
23 views

The confusion regarding friction [duplicate]

I have read that friction is caused due to electrical force of attraction between the two surfaces. Rougher the surface, the number of contact points is less. Therefore I think on smoothing the ...
0
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1answer
156 views

Block being pulled from rest on a frictional surface [closed]

An initially stationary block of mass $m$ has a force, $F = 0.500mg$, applied to it at an upward angle $θ = 20˚$ above the horizontal. What is the acceleration of the block if the frictional ...
-1
votes
1answer
119 views

What is the force that stops a rotating wheel eventually? [duplicate]

Assuming a car is traveling on a road. At some point, the driver stops accelerating the car, so it travels some distance and then stops. Since the car's wheels are round and are rotating without ...
0
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1answer
50 views

Definition of unit of force [closed]

As we know $1\ \mathrm{N}$ is the force which can accelerate $1\ \mathrm{kg}$ mass with $1\ \mathrm{m/s^2}$ acceleration. But for which surface is this definition given? I mean a $1\ \mathrm{kg}$ ...
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1answer
192 views

What does the free body diagram for mass 1 look like?

In this situation: Enough tension is applied towards the right on $m_2$ so that $m_1$ starts sliding backwards. I am confused about what the free body diagram for $m_1$ looks like. Here is my ...
0
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1answer
38 views

The Frictional Anomaly [duplicate]

Its a question I have read in a book, that, When two surfaces are polished, the frictional coefficient decreases. But if the surfaces are made highly smooth, the frictional coefficient increases ...
1
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0answers
165 views

Can iron filings on a magnet be removed using a stronger magnet?

After some experiments, I had some NdFeB permanent magnets "contaminated" with iron filings, sticking to it's poles surfaces/edges - you may have seen that before. There are some working ways to ...
0
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1answer
85 views

Circular motion with friction (time dependent velocity)

I am trying to understand how circular motion problems can be solved when we introduce friction as a variable in them. As i understand this problem, the centripetal force, which points towards the ...
0
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1answer
108 views

Measuring friction coefficient with a inclined plane. Beetle problem

I want to measure friction coefficient between a beetle and an inclined plane (angle of inclination $\theta$). As we all know, friction coefficient $\mu$ is given with: $\mu=tg \rho$, where $\rho$ is ...
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2answers
126 views

Is friction a function of surface area? What is the microscopic workings of friction?

I know the friction is given by the following equation $$\mu F_N=F_f$$ which tells me friction is independent of surface area, but how do I characterize it as such if I want to add surface area into ...
0
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1answer
58 views

What is the difference between damping and friction?

What is the difference between damping and friction? Both of them slows down any moving system. So whats the conceptual difference between them?
1
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1answer
108 views

Air friction at supersonic velocities

I know that if an object moves in the air, it can experience two types of drag, laminar and turbulent. For instance, I have a meteor of ideal spherical shape falling from edge of space, say, 100 km up ...
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0answers
57 views

Friction of an object falling between two walls

I'm simplifying this problem into 2D for easier understanding. Lets say we have 2 vertical walls separated by distance x. Inside these walls I place an object that is only slightly smaller than x in ...
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2answers
524 views

Positive work done by friction

Can work done by friction be positive? Please explain with an example. Is the work done by friction on a moving car positive?
0
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2answers
134 views

How far would the car skid when brakes are applied? [closed]

Suppose that a car skids $15$m if it is moving at $50$km/h when the brakes are applied. Assuming that the car has the same constant deceleration, how far, in meters, will it skid if it is moving at ...
0
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3answers
73 views

Kayaking against the wind is faster than with wind in my back? [closed]

Today I was kayaking on a lake. I noticed that there is not very strong, but noticeable wind. There were also currents, all going in one direction, probably caused by wind. One more thing I realized ...
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2answers
241 views

Temperature rise during friction

Why does the temperature increase when the load increases during friction? Why does the temperature increase when the contact time increases during friction?
-1
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2answers
539 views

Block over a Block Problem. [closed]

This a block placed on block problem. In this problem, A block with mass 40 kg in placed on a block of 60kg which lies on a frictionless surface. The coefficient of friction between 40kg mass and 60kg ...
-1
votes
1answer
94 views

Time taken for sliding mass to fall down [closed]

Figure shows a small block of mass m kept at the left end of a larger block of mass M and length l. The system can slide on a horizontal road. The system is started towards right with an intial ...
33
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3answers
6k views

Push a Boeing 737 on ice: Did this guy have a chance? [closed]

In this video an airport worker (in blue) tries to prevent a Boeing 737 from sliding on ice in heavy winds: Did he even have a chance? On one side of the argument, the airplane is sliding due to ...
1
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1answer
101 views

Rolling down an arbitrary hill with friction

I had in mind this physical situation of a point mass rolling down a hill of some arbitrary shape ($y=y(x)$, for instance a parabola about $x=0$), with a peculiar friction force whose "expended work" ...
0
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1answer
114 views

When you smooth-en a surface at microscopic level, friction increases. Why?

When I was learning a chapter related to Static electricity, my teacher had mentioned that when you rub your comb with DRY hair specifically, static electricity is generated due to friction. Further ...