# Questions tagged [friction]

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

1,623 questions
Filter by
Sorted by
Tagged with
2answers
144 views

### 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 ...
2answers
73 views

### 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. ...
3answers
85 views

### 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 ...
1answer
70 views

### 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 ...
3answers
94 views

### 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 ...
1answer
84 views

### 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, ...
3answers
96 views

### 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 ...
0answers
57 views

### 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 ...
1answer
245 views

### 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 ...
0answers
22 views

### 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 ...
9answers
12k views

### 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 ...
1answer
32 views

### 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 ...
1answer
22 views

### 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 ...
6answers
178 views

1answer
133 views

### $μ = \tan\theta$ - Why? It makes sense mathematically, but if it's based on the materials how does that work?

We were presented with a problem in physics today in which we calculated that the coefficient of static friction is equal to the tangent of an angle This is on a ramp using the laws of friction. My ...
1answer
5k views

### Friction between two blocks on top of each other

I am a little bit confused to the concept of friction between two blocks on top of each other. there could be two situations: the first situation is when all surfaces are frictionless including that ...
2answers
71 views

### Special cases in friction [closed]

Imagine that 2 objects are stacked. The friction between the objects is higher than the friction between the bottom object and the ground. Is it possible for the top object to be pushed hard enough to ...
2answers
108 views

### Dynamics of a sphere in a horizontal plane driven by a force

I'm studying the dynamics of a sphere in a horizontal plane driven by a force. The situation is the following: I have a stationary sphere of mass $m$ and radius $r$ in a pool table whose lining has ...
1answer
27 views

### Dynamic friction

In my house, we are debating whether when you scrub the floor it is easier or more difficult to drag a piece of furniture. My floor is made of marble, who's right?
2answers
31 views

### Displacement using work energy principle

How do you use the work energy principle to find the displacement of an object. With of course the mass, speed and friction forces given?
1answer
132 views

### rolling friction of a solid sphere

This may be a very rudimentary question. I have two spheres on a physics simulator and I need to define various parameters including rolling friction, spinning friction, inertia, color etc. I was ...
3answers
229 views

### How long does a coin take to slide off a turntable?

So I was helping my daughter prepare for a AP physics test. I studied Physics at university many many years ago and always assume I'll be able to figure out any reasonable question about mechanics. I ...
1answer
219 views

### Maxwell's wheel and friction

We experimented with the Maxwell's wheel today and at the end we were asked about why does this apparatus stop since there is conservation of energy. I did some research and apparently there is a type ...
2answers
204 views

### Work done by friction on a body which is rolling on an inclined plane [closed]

Why is the work done by friction zero during translational motion but nonzero when the body is rolling on an inclined plane?
3answers
164 views

### Basic question on friction

Consider the whole system initially at rest.Suppose there is friction between the blocks, but not between the lower block and the floor. Suppose I apply a Force F to the left over M, with F greater ...
1answer
51 views

### Damped oscillations and generalized friction

I'm reading damped oscillations from the book Classical Mechanics by Landau and Lifshitz, quoting from the text - "There exists, however a class of problems where motion in medium can be ...
0answers
35 views

### How friction works? [duplicate]

I learned that friction comes from the tiny crashes between the small bumps of uneven surface of each object. And I could make a rough guess about why heat is produced when two objects are rubbed ...
1answer
466 views

### How does one mathematically derive the damping coefficient of a theoretical viscous dashpot?

I am very well aware of how to get the damping coefficient experimentally by observing a system in action. Given the dimensions and fluid properties of a theoretical viscous fluid dashpot, how does ...
1answer
69 views

### Dependency of kinetic friction [duplicate]

1.Why kinetic friction doesn't depend on speed of object? Also explain why static friction > kinetic friction > rolling friction? 2.when we keep a book on a table , the table is said to exert a ...
3answers
45 views

### Rolling friction and motion [duplicate]

The frictional force in a motion of a rolling body is along the direction of motion. Then what stops the motion of a rolling body?
1answer
164 views

### Finding the frictional coefficient

This is going to be very long question. A 1 kg block situated on a rough incline is connected to a spring constant 100Nm as shown in fig. The block is released from rest with the spring in the ...
2answers
125 views

### When you have engine at idle and turn your car, where does the kinetic energy go?

When you turn the front wheels to the right for example, your car will tend to continue in its original forward direction. However, there is friction between the wheel and the ground that prevents it ...
1answer
45 views

### How far does a teflon ball roll on a very even surface? [closed]

As teflon has a minimal frictional coefficient of about 0.04, how far does a ball made of teflon roll on a even surface in comparison to another ball (made of wood or iron, for example), when pushed ...
1answer
26 views

### Damping in a stick-slip model

Usually the spring/block stick-slip models also include a damper. eg: https://nptel.ac.in/courses/112102015/10 I don't really understand the purpose of the damper. What does it represent? Also, ...