Questions tagged [friction]
The resistance a surface or object encounters when moving over another.
2,389
questions
0
votes
1
answer
17
views
What does the position $x(t)$ looks like in an overdamped system?
I know that for the position $x$ as a function of time in an underdamped system (such as a mass on a spring) you can use the function:
$$x(t)=Ae^{\gamma t}cos(\omega t-\phi),$$
where
$$ \begin{split}
...
0
votes
2
answers
26
views
Why power of engine must be equal to power of friction?
Suppose a car with electrical engine moves uniformly with friction between wheels and the ground (neglect air resistance, energy loss, etc.). So why the car's engine power must be equal to friction's ...
-1
votes
0
answers
9
views
How are the tipical values of the Columbus and viscous friction torque?
I am mathematically modeling a motor and I want to calculate the constant columbus and viscous friction torques. The forumula I found was:
where a is the voscous friction torque and b is the ...
- 1
0
votes
3
answers
41
views
Is the deceleration a result of friction, a constant value?
Frictional Force = km, therefore k = a
Would this mean that no matter the mass of an object (if they are the same material)
They will decelerate at the same speed with friction, therefore if u is the ...
- 3
0
votes
2
answers
52
views
Problem with possibly infinite possible solutions [closed]
Problem figure:
In the problem, the string is light, inextensible and initially, before the application of the external forces, the string is just taut with no tension and the blocks were at rest. ...
- 197
2
votes
1
answer
51
views
Dependence (or lack thereof) of forces on frames of reference
Consider a block A on top of block B with a coefficient of friction of say 0.3 in between them and the path providing zero resistance (no friction), with the bottom block moving such that its ...
- 25
0
votes
3
answers
50
views
Does a vehicle experience any friction while its wheels roll with a uniform velocity?
Rolling friction supports forward motion of the rolling body. So acceleration of the body equals friction/mass. While moving with uniform velocity, a=0, so friction should also be 0.
9
votes
1
answer
701
views
Intuition behind the differential equation for forced oscillations
The differential equation for forced oscillation is:
$$m \ddot{x} + b\dot{x}+kx = F_{o}\sin(\omega''t)$$
I don't find this equation intuitively satisfying. My mind tends to think that as $F_{o}\sin(\...
- 225
-1
votes
2
answers
50
views
Friction when a car is moving in a circle
When a car is moving in a circle, I want to know how the friction of the car could be drawn.
I have found the following picture. But I know that the friction force is always in opposite direction
of ...
1
vote
5
answers
143
views
Is work done by torque due to friction in pure rolling?
This question has been asked and answered numerous times. I went through almost all of them and found no consensus. I found that all of the answers can be divided into two categories:
Friction does ...
- 943
4
votes
2
answers
78
views
About Contact, Normal and Friction force
I'm currently studying Friction $f_a$ and Normal force $N$, and I read that those two forces are nothing but the parallel and perpendicular components of a "general" force called Contact ...
7
votes
3
answers
406
views
Would it be possible to ride a bicycle on the surface of Mars?
Could you ride a standard bicycle on the surface of mars?
Assumptions:
You are wearing a suit to provide life-support
You are riding on a prepared smooth flat martian 'road'
If you were to ride ...
-1
votes
0
answers
35
views
Determine the trajectory of a ball on a golf green that is not level
I want to determine the path of a golf ball when someone "puts" from a location on the "green" to the "hole". The distance between the location of the ball and the target/...
- 99
0
votes
0
answers
61
views
Kinetic friction and damped harmonic oscillators
I was taught in school that the magnitude of the kinetic frictional force does not depend on the speed.
Hence, the equation of motion of the harmonic oscillator in the presence of friction with the ...
- 15
0
votes
2
answers
55
views
Is change of angular momentum of two rotating disks colliding w.r.t. time $L(t) = \omega_0 I(1-e^{-t/C})$?
If you have two rotating disks with a different angular velocity $\omega_0$ and $\omega_1$, different area and material, how can you describe the angular momentum w.r.t. time which seems to be a ...
- 938
0
votes
1
answer
56
views
How to describe a series of damped harmonic oscilators?
I am looking for textbooks or papers that provide an analysis for a series of damped springs. I am having a tricky time working out the details on my own. I know that if $F=-k\Delta x$ a series of ...
- 5
2
votes
2
answers
140
views
Shouldn't length contraction cause friction under certain circumstances?
I was thinking about the ladder paradox, which if I understand correctly involves a combination of length contraction and relativity of simultaneity. And with that it is resolved.
But there's this ...
- 29
0
votes
0
answers
9
views
Explaining how charging an object (classic experiment) work [duplicate]
In the classic experiments two objects are rubbed and an asymmetry appears.
If one of these objects touches or is close to a conductor there is a spark (like a lightning to earth).
If it touches ...
- 1
0
votes
2
answers
46
views
This question is about motor power requirements
If I have a motor that has a power of 20 kilowatts, does that mean that the motor can produce a torque of 10k newtonmeters at 2 rpm, or analogously a torque of 2 newtonmeters at 10k rpm since the ...
- 1
2
votes
1
answer
52
views
What is the real cause of friction? [duplicate]
sir i have studied through various websites. there i found two theories-
friction is due to inter molecular bonds which forms when two surfaces kept together.
now if it true then why do we not feel ...
- 43
1
vote
2
answers
65
views
Why does a pulley rotates?
I have beening dealing with problems involving pulleys. It seems like a pulley is something that changes the direction of a string, and it rotates when the string moves on it.
Why do we need something ...
- 207
0
votes
0
answers
26
views
Resources to learn about rolling resistance
I have been going through static and kinetic friction in my introductory physics courses. However, in problems involving rolling, I was struggling to understand the paradoxical results that come from ...
1
vote
2
answers
67
views
Why does Friction not accelerate the body in this case?
My textbook says (see the highlighted paragraph below), "Normal is the perpendicular component of contact force, while friction is the parallel component".
First of all, I am familiar with ...
- 806
0
votes
3
answers
62
views
Why does acceleration not depend on mass down an incline?
I understand the net force acting on toy car traveling down an incline is:
F = mg sin θ - μ mg cos θ
a = F/m
Hence mass cancels out leaving: a = g(sin θ - μ cos θ).
Intuitively I can't understand why ...
1
vote
1
answer
18
views
Mass effects on toy car
In a theoretical experiment with only friction ( With floor and ramp ) and gravity, would the mass of a toy car affect its distance traveled after reaching the bottom of the ramp.
My hypothesis is ...
0
votes
4
answers
52
views
Path dependence of non-conservative forces
In almost every place the statement regarding non-conservative forces is:
In the case of non-conservative forces, the work done is dependent on path taken between two fixed points. Longer the path, ...
- 11
2
votes
2
answers
75
views
Does mass affect distance travelled by a toy car?
Say, I conduct an experiment with a toy car and a ramp (Fixed angle). If I were to use the same toy car but place different weights on it (assuming the same size and shape), would the car with more ...
- 41
2
votes
4
answers
102
views
How does friction work?
Scenario 1:
Here, $O$ is the center of mass of a uniform, rigid and solid block. $F_g$ is the force of gravity acting on the body vertically downward, and $N$ is the normal force acting on the body ...
- 754
1
vote
0
answers
49
views
Car with different mass travelling down a ramp
Recently I conducted an experiment at school to see if mass affected the distance travelled by a car after reaching the bottom of the ramp. We used the same toy car and placed different weights on the ...
- 41
0
votes
0
answers
22
views
What is the difference between kinetic friction and internal kinetic friction?
I came across the following question in my homework assignment:
Which of the following statements is TRUE for a system comprising of two bodies in contact exerting
frictional force on each other :
(A) ...
- 15
1
vote
2
answers
51
views
Object moving down an inclined plane and an object moving along a banked road [duplicate]
Why is the normal force of an object sliding down an inclined plane equal to mgcos(θ), whereas for an object moving along a banked road, the normal force of the object is mg/cos(θ)? Also, in some ...
- 73
1
vote
1
answer
41
views
How do objects slide under one another?
I am making a small Robot to pick up things off the ground, and I am trying to understand the physics behind objects sliding under one another. The exact scenario that I am talking about in real life ...
6
votes
2
answers
747
views
How can I test relative friction at home?
My 7 year old is anxious to test whether or not banana peels are slippery. He has been waiting for 2 years for the science fair to come back. We have the idea to test different types of banana peels (...
- 69
2
votes
0
answers
40
views
Why doesn't angular frequency change in damped simple harmonic motion?
I recently carried out an experiment varying different factors affecting simple harmonic motion, namely friction and air resistance. Whilst carrying out research for this, I found the relationship ...
-2
votes
1
answer
84
views
A Question What is wrong in my Gedankenexperiment? about the Conservation of energy [closed]
Please excuse my English...
Let's say we have a 10m x 10m x 10m water tank filled with water.
After a little search i found that the pressure on the sidings at 9-10m depth would be approximately -> ...
- 19
-1
votes
2
answers
63
views
Equation of velocity against varying frictional force
I am trying to find an equation of velocity for a point like object during its motion along a rough circular path. I know that if I could use the law of conservation of energy it would be way easier ...
0
votes
1
answer
68
views
Motion along circular surface [closed]
The question goes as follows (translated):
An object slides down a circular path with radius $r$ . The object has its maximum speed $v$ when the slope of its trajectory is $α$. Find an expression for ...
- 1
0
votes
0
answers
14
views
Model of a box hit by a Force or Given an Initial Speed
What would be a good way to model a box in a horizontal plane that is hit with a certain blunt force in order to move it some distance. What would be a good mathematical model given that the box is ...
1
vote
3
answers
64
views
Maximum static friction
Given a maximum applied force $f_{\text{max}}$ on a particle with normal force $N$, if the force is parallel to the surface then I'm told that the static friction of surface is given by $$\mu_s=f_{\...
- 121
2
votes
2
answers
53
views
What happens when I grab a rope after jumping down?
If a body has a mass of 54 kg and falls straight down for 11.33m before grabbing a rope, what are the forces acting here? What part does the coefficient of friction between the rope and hand play?
- 21
3
votes
1
answer
192
views
Modeling friction with Non-Lipschitz ODEs - Pendulum example
The main objective of this question is to figure out if the following differential equation have [finite-duration] solutions:
$$ \ddot{\theta}+0.021\,\operatorname{sgn}(\dot{\theta})\sqrt{|\dot{\theta}...
- 73
0
votes
0
answers
56
views
No-circular motion on a turntable
As the title says, I want to model the path of an object sliding on the surface of a turntable, as it is slowly flung off.
The final application of this is , modelling fine material moving along the ...
1
vote
3
answers
39
views
How to know which coefficient of friction to use?
I need to find the friction force acting on a body with known mass using the coefficient of static or kinetic friction. The formula for friction force is
$$F = \mu N$$
Which coefficient of friction ...
- 47
0
votes
0
answers
19
views
When objects are charged via friction, what are the objects' initial charges?
When objects are charged via induction, one object is initially charged and the other is initially neutral.
When objects are charged (or neutralized, in this case) via conduction, one object is ...
- 33
0
votes
2
answers
33
views
Microscopic model for difference in kinetic and static friction
It is commonly taught (and also seen in experiments) that generally speaking the static friction coefficient is always greater than the kinetic coefficient, in other words
$$\mu_K<\mu_S$$
I have ...
- 608
0
votes
0
answers
13
views
How to calculate the surface heating of the ball thrown in different fluid mediums like air and water?
Let's say a ball is thrown at a certain velocity, then it follows a projectile motion and falls on the surface. Now, during this entire flight how can we calculate the temperature rise that happens in ...
- 101
-2
votes
1
answer
44
views
How will a car with two locked wheels go down from an inclined plane? [duplicate]
I asked a question earlier about a car going down an inclined plane. The front wheels are locked and the rear wheels are free to move. The car goes down while the front wheels slip.
I thought that the ...
- 1,572
0
votes
0
answers
29
views
Friction in mass energy equivalence
Here it has been pointed out that as a body receives energy $E$, it's mass increases by well by an amount $\frac{E}{c^2}$. In the question given, friction has been considered. Now we know work done on ...
- 569
0
votes
1
answer
46
views
Why its easier to tie things with multiple loops to the thread for hanging from a pivot? [closed]
We often see that hanging a object by looping a thread around a pivot many times will make the thread to not fall off, but when looped less than critical needed the object falls off, is the friction ...
- 485
0
votes
1
answer
50
views
How does damping constant relate to mass?
(Moderator note: this question is not answered by a different post here)
In damped harmonic motion, I'm led to believe that the equation of motion in a mass-spring system is as follows
$$x = Ae^{-λt} ...
- 13