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

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0
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2answers
38 views

Difference between stiffness and damping?

I understand stiffness as the extent to which an object (e.g. a mass spring) resists deformation from an applied force, or the rigidity of an object. And I understand damping as the energy ...
-1
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2answers
37 views

Circular motion and inclined friction

I'm given the following picture: A car with the mass m passes the top of a hill with the height H. The coefficient of friction is $µ$. The speed of the car is $v_0$ in the moment of braking. ...
2
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1answer
252 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 ...
-2
votes
0answers
31 views

What is $T_1$ and what is $T_2$ in Capstan law?

How do I determine which force is which (T1 or T2) in the Capstan law? In case there is no rotation and in case there is rotation of the capstan.
0
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2answers
24 views

Will kinetic friction change when normal force and coefficient of friction remains the same?

Based on common knowledge, a car can do uniform motion in any velocity when the applied force(by engine) do not exceed the maximum kinetic force of friction which can be calculated by: $$\ F_f = \mu_k ...
1
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1answer
18 views

The instability of dry friction

Based on Newton Dynamics, the kinetic force of friction of any moving object can be found by using formula, $$F_f = \mu_k F_N $$ This means that if $\mu_k$ and $\ F_N$ remains constant, the ...
2
votes
0answers
25 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 ...
1
vote
1answer
67 views

How to calculate torque required? [on hold]

Here's my problem diagram: I am working on a hobby project in which a motor is required to rotate a pulley that is connected to a pendulum as shown in the image. The maximum torque, Horsepower and ...
0
votes
2answers
40 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 ...
0
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0answers
20 views

Pendulum with Viscous and Frictional Damping

I am trying to model a pendulum with both viscous and frictional (Coulomb) damping. The problem is that the viscous damping only occurs in one direction because I am modeling a dashpot that only has ...
1
vote
1answer
14 views

Do dimples reduce laminar drag across a surface?

My question is about laminar flow across a smooth surface. I have read about how the eddy currents, caused by dimples, at the surface help a blunt object travel through the air with less drag as in a ...
0
votes
1answer
44 views

Friction of a scissor [closed]

How can the friction by a scissor blade be related to its angle? To be more specific this is the question that I came across. A scissor is used to cut a wire of circular cross section and ...
6
votes
1answer
571 views

Lagrangian and Hamiltonian EOM with dissipative force

I am trying to write the Lagrangian and Hamiltonian for the forced Harmonic oscillator before quantizing it to get to the quantum picture. For EOM $$m\ddot{q}+\beta\dot{q}+kq=f(t),$$ I write the ...
0
votes
1answer
231 views

Inclined plane, circular motion and the friction

Suppose we have a cylinder on an inclined plane of mass $m$ and radius $R$ moving without sliding (so that $\varepsilon = a/R$). Why is the friction $F$ causing the circular motion sometimes lower ...
0
votes
1answer
20 views

Problem involving Energy Method and Non-conservative Forces [closed]

I've got a problem in my physics I class that's got me stuck at the moment. A box is placed onto an angled plane so that it compresses a spring. When released, how far up the plane does the box go? ...
0
votes
1answer
17 views

When to consider friction as an impulsive force?

Suppose a ball obliquely strikes a rough horizontal surface then it experiences a frictional impulse and conservation of linear momentum cannot be done on the horizontal direction. Now consider ...
2
votes
3answers
126 views

Where does the energy go when engine braking?

If you're in gear in a car and not accelerating, the car slows down faster than it would from just air resistance and tire deformation. In normal braking, the energy is turned into heat from the brake ...
1
vote
2answers
29 views

How can you tell if the work done by a force is negative?

This is kind of confusing to me. I'm guessing that it's specific to the problem. Is the work done by friction always negative? Is the work done by gravity always negative? Spring as well? It seems ...
3
votes
2answers
264 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 ...
0
votes
1answer
206 views

We cannot solve this inclined plane problem, right?

We drag a sledge along a snow-covered hillside with constant speed. Distance is 150m. The time it takes to reach the top is 300 secs. The sledge is 12kg. And the coefficient of friction $\mu$ = 0.04. ...
0
votes
0answers
15 views

Can a 2 HP motor move a 1,000 lbs flat-bottom boat across a flat material surface? [migrated]

There is a small 13' long x 6' wide, 1,000 lbs (total weight of everything) all-fiberglass white pontoon boat with dual flat-bottom fiberglass pontoons. (Each flat pontoon bottom is 2' in width, with ...
6
votes
5answers
138 views

A conceptual doubt regarding Forced Oscillations and Resonance

While studying about the Resonance and Forced Oscillations, I came across a graph in my textbook that is given below:- Now, the author writes As the amount of damping increases, the peak shifts ...
1
vote
1answer
186 views

How can angular velocity be constant even when there is a torque by friction?

A cylinder at rest lying on a rough ground is given an impulse which imparts a translational velocity (no angular velocity) to it. The question goes ahead with finding time after which rolling starts ...
0
votes
1answer
36 views

Friction forces on stack of blocks

Consider a block sliding on a surface, with friction between the two. The friction force will be equal to $\mu N$, where $N$ is the normal reaction force, which is usually equal to $mg$, where, $m$ is ...
3
votes
1answer
576 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 ...
0
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1answer
41 views

Angular Acceleration of a Pendulum

I am trying to work out the mathematics behind the design of an old mechanical brake tester. The device sits in the passenger foot well of a vehicle and tests the brake efficiency. The device is ...
11
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7answers
1k views

Why doesn't an object, despite having a non-zero potential energy stored in it, fall by itself from the elevation?

When an object is at a certain height, it has some energy stored in it as we have done some work on it to get it to that height. So when it already has energy, then why doesn't it fall off from the ...
0
votes
1answer
13 views

Increasing frictional force without increasing normal force

Is it possible to achieve 10N of frictional force while only having 1N of normal force, using a coefficient of friction no greater than 1? My grade 11 physics teacher is asking us to do this. He ...
0
votes
1answer
35 views

Rheological Definition of Friction

I was listening to a record at our university about friction and its rheological definition. For the first moment I thought that its the normal definition Friction is the force resisting the ...
0
votes
1answer
157 views

Explanation about friction force directions of two moving bodies in contact

can someone explain me why in this scenario (picture below) we have a friction force Ftr12 in the same direction as movement (left part of the picture, case 1 ) and how these directions of friction ...
0
votes
1answer
119 views

Work done by friction on a body?

I know that when a body slides over a surface, the work done by friction is not stored as potential energy in the body. It is dissipated in the form of heat. But why is it not stored as potential ...
6
votes
3answers
9k views

why making a surface “super” smooth increases the coefficient of friction?

I read that: If you take a rough surface and make it smooth, the coefficient of friction decreases. But if you make it super smooth, then the coefficient of friction increases. How come?
0
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0answers
20 views

Force conversion in a barrel cam-follower mechanism

A barrel cam-follower mechanism consists of a (cylindrical) barrel with a cam track, a cam-follower (roller) inside of the track, a fork connected to the cam-follower and a guide along which the fork ...
1
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0answers
9 views

pulley friction difference between static and sliding surfaces

the pulley friction question for static cases is T2/T1=e^μθ. When the surfaces between the belt and the wheel slide, how can we determine the friction? Is it the same friction? Is there a different ...
0
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2answers
30 views

Why does limiting friction have to act when a block tied to a wall is pulled?

A block lying on a rough surface, is connected to a wall by a mass less, inextensible string and an unknown amount of force is applied to the block opposite to the side of the wall. Now, if it is ...
0
votes
1answer
20 views

Understanding role of friction in block on block problems

Consider two blocks stacked on top of one another. There is friction between the blocks but there is no friction between the lower block and the table. So the only frictional force that tends to ...
0
votes
2answers
188 views

Damping Constant for a Ball Rolling in a Bowl

How would you find the damping constant of a ball rolling without slipping in half of a sphere? I know how to find the period of the oscillation, but how would I find the damping constant ...
0
votes
1answer
149 views

Consistent method for finding direction of static friction

I am having trouble coming up with a consistent method of determining the direction of static friction. So far the best I have come up with is: it should oppose the relative acceleration the contact ...
0
votes
3answers
2k views

Different directions of frictional force when objects are rolling

My textbook has two instances of rolling bodies (smooth rolling). In the first, the body is rolling on the horizontal floor with some acceleration of its centre of mass. In this case, the book says ...
1
vote
1answer
56 views

How I think about rolling [closed]

Below, I have written how I think about rolling. I wish to know if my idea as to how it works is correct. Consider a rigid ball on a plane which has considerable friction. If you push the ball ...
22
votes
14answers
8k views

Is it possible to walk in a friction-less world?

Is it possible to walk in a frictionless world. I think you won't be able to walk because walking depends on friction acting on your feet. I think about it like an ice rink because when you try to ...
1
vote
1answer
33 views

Dissipation and first law of thermodynamics

Consider the following situation: a certain gas is contained in a well-insulated cylinder with a well-insulated piston head. Now, in this case the piston is not frictionless. In order for the piston ...
0
votes
1answer
26 views

Question about friction in rolling without slipping?

I was under the impression that for a ball/cylinder to roll without slip, there must be a static friction force that opposes the direction of motion. Why, in this case, does the friction act in ...
1
vote
0answers
35 views

When will a moving vehicle stop faster: when the brakes are applied and the wheels are slipping, or just before? [closed]

When will a moving vehicle stop faster: when the brakes are applied and the wheels are slipping, or just before the wheels start slipping? Explain why.
0
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3answers
816 views

Why does a ball roll?

I searched for my question and I found many results but all of them eventually try to solve something specific (like solving for the kinetic energy or finding when does the ball stop). what I want ...
0
votes
1answer
465 views

Block Sliding Down a Plane (Perpendicular Velocity)

I'm having trouble understand the concepts for this problem. Here's the problem: A block is placed on a plane inclined at angle $\theta$. The coefficient of friction between the block and the ...
4
votes
3answers
283 views

How does mass affect the distance a ski jumper travels

I did an experiment to explore this. My results found that their is an optimum mass of a ski jumper. I am unsure about the maths behind this. Can anyone help.
2
votes
1answer
253 views

Maximum angle for highway lane change

I am preparing to fight a traffic ticket from a speed camera. There is a lot more to that story, but the info I need right now involves the angle at which a car can change lanes, in terms of vehicle ...
0
votes
0answers
28 views

Find the maximum force P that can be applied for which the blocks do not slide and their respective acceleration

Two blocks are on an inclined ramp of 35 degrees. Block A is on top of block B. Block A weighs 36 lbs and block B weighs 18 lbs. The coefficient of static friction between the two blocks is 0.45 but ...
0
votes
1answer
162 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 ...