Questions tagged [friction]
The resistance a surface or object encounters when moving over another.
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Confusion between the contact force in string
My textbook says that when two bodies are in contact there exist a contact force between them and it has two components also one is perpendicular to the surface and the other is parallel to the ...
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My book states that contact force between two surface is equal to $\sqrt{N^2+F^2}$. where $N$ is the normal force and $F$ is the friction
Applied Force is our label for a contact force that a person exerts. When an applied force acts at an angle, it is actually a combination of two forces: normal and friction. The component of the ...
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The dreaded incline plane [closed]
Source: Principles of physics 11th edition halliday Chapter 6 Q11.
Yes, this is a homework question and I am questioning my misconceptions. Answer at back says 3.9m/s^2 downwards.
Standard inclined ...
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A system of two blocks and string are kept on two inclined faces (rough) as shown in the figure below. Find the range of the tension in the string? [closed]
A system of two blocks and a light string are kept on two inclined faces (rough) as shown in the figure below. All the required data are mentioned in the diagram. Pulley is light and frictionless. If ...
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Car rolling away on an Inclined Plane with friction [closed]
I am trying to refresh my physics skills. I am having an exercise in which a 4-wheel-vehicle is on an inclined plane with friction, and rolls away (no braking, no air resistance, no Center of Mass is ...
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Friction & Normal Reaction
P= Pulling
Any reference for the gradient of Normal Reaction.
Will pushing the weight lead to reversal of gradient?
Does this mean there is gradient of friction force (as it depends on normal reaction)...
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Do conservative forces obey Newton's laws of motion? If we look closely, non-conservative forces like Friction etc follow 2nd law but Im confused [closed]
I have a small confusion, do conservative forces obey Newton's Second Law always?
Because it depends on the end points and the path taken, the acceleration may vary path to path, but the force doesnt ...
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Equation of a bicycle Wheel in free rotation up to stop
I have measured the rotational speed of a bicycle wheel in free rotation up to stop and i would like to have the physical equation (it is not linear). I would like to compute the frictional losses in ...
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A conceptual doubt about friction acting on a car
Suppose a car is at rest and you apply the accelerator, then the wheels are applying a horizontal force on the road so according to Newton's third law an opposite force (friction) pushes you forward. ...
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Signum function and friction
There've been some times where I've seen people including the signum function, $\text{sgn}(v_x)$ in equations of motion to account for the instant when the horitzontal velocity component, $v_x$, ...
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Why is it more difficult to turn the steering wheel of a stationary car than a moving car? [duplicate]
I believe anyone who has driven a car without power steering has noticed this effect. I am not able to find a justifiable argument online. My thought process suggested it must have to do something ...
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Why does in open belt drivers systems the angle of lap is taken from the angle of the smaller pulley and not the bigger? or viceversa [closed]
I am studying power transmission in flexible mechanical elements (flat belts) and I don't know why everyone takes the angle of lap as pi - 2sin-1(D-d/c) and not pi + 2sin-1(D-d/c) why use the smaller ...
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Clarification on the Application of Newton's Second Law [closed]
I'm having trouble understanding how to apply Newton's Second Law in certain scenarios. I understand the basic equation $F = ma$, but I'm confused about how to use it in situations where the forces ...
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Why are my heavier objects sliding on a smaller incline than lighter objects? Coefficient of Static Friction
I gave my students a lab on the coefficient of friction in 2D. I use a wooden plank and sandpaper as my IV. I have done this experiment in a few different ways, but the normal consensus was still the ...
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Problem in understanding path dependence of friction
I was trying to solve this question, and I thought I did until I saw the solution. This is a standard problem in classical mechanics.
A ball of mass $m$ is slowly pulled along an irregular rough ...
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When is work done NOT frame dependent? [closed]
In general, we know work done by a force depends on frame of motion of observer, but this is not always the case,
for example, take the case of static friction and consider the NET work (sum of work ...
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Why is there a limiting value of friction (to avoid slipping) when driving in a circle
When thinking about this in reality and using equations I come to different conclusions.
Using F = mv^2/r
In reality I know that if the speed is too fast the car will not be able to go around the ...
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Ball slides down
I've kept a ball between one fixed and another mobile surface of same height (say two books one which functions as a fixed support while other is moved on about by me). While I pull one of the books, ...
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Which friction acts on on a Rolling body? [closed]
First question is, is it static or kinetic friction which acts on the rolling body or both do?
Say we give a body (sphere lets say with radius $R$) with NO ANGULAR VELOCITY, just linear. Say we ...
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Friction on a rolling body [duplicate]
I have been reading about rolling motion and I seem to have a confusion regarding the friction acting on such bodies.
First off for a body to start rolling their has to be some friction b/w the ...
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Why is the coefficient of static friction used in the formula for the stopping distance when there is no relative motion between tyres and road?
Instead of using the coefficient of static friction between the tyres and the road, should we not use the coefficient of kinetic friction between the brake pads and the disc?
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Why adding weight to a motorcycle increases the stoppage distance?
I was doing my car license's questions, and it came up this question, why would the stoppage distance (the distance which the car stops after breaking) increase if you add more weight on top of the ...
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What is $b$ in this formula of friction force?
I have seen a formula of friction force,$\vec{F}=-b\vec{v}$
I know $\vec{v}$ is velocity,but what is $b$?
Is it damping coefficient or friction coefficient?
Or damping coefficient or friction ...
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How much work am I doing here?
If I pull a block horizontally with a rope, I am pulling with a force of $20$ N and there is $10$ N of friction resisting the motion.
I want to calculate the work done: $$W=Fd$$
Is $F$ my total force $...
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When the static friction is the centripetal force, what is the opposite force?
Consider a circular horizontal plane (like a round tabletop) rotating around its center.
Consider a body A resting on this tabletop. Since the tabletop is rotating around its center, the body is ...
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Opening a tight cap of a bottle of water
Just a curious question that came to my mind a few days ago. Say we have a tight cap of a bottle of water, we know that the kinetic friction force is smaller than static friction, so then I thought, ...
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In which direction does static friction acts on the spool when a force is given to it below centre of mass?
Here, we are provided with a spoolhaving moment of inertia I=kmr², where k is a numerical factor.
I am in the confusion that how should we judge in which direction static friction would be applied,
I ...
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Work done by Kinetic Friction [closed]
Which of the following is true for a system comprising of two bodies in contact exerting frictional force on each other.
a)total work done by static friction on system is always zero
b)work done by ...
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Why can a car skid if you take a curve too quick?
I've seen loads of cars that skid during a curve due to taking it with a high velocity. I can guess that it has to do with the grid with the road and maybe something to do with centifugal forces?
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Magnets without friction
Let's say a small magnet is attached with its South pole on to the north pole of a bigger magnet vertically.There is no friction between the magnets so this means the normal force increased due to the ...
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How to balance forces in a loop-de-loop?
Imagine a car is going up a loop de loop and we look at the forces at the top of the loop.
If the car is of a sufficient speed, then it doesn’t lose contact with the surface.
This makes sense from the ...
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In wheels that roll without friction, why don't we include the centripetal force? [closed]
Suppose we have a wheel rolling on a surface that has friction coefficient $\mu$ and it has velocity $v$,radius $r$, and mass $m$. When I calculate the Normal force for this wheel in order to ...
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How can I calculate accurate energy loss that occurs in a compound pendulum?
I want to find out the energy loss that occurs in a compound pendulum. Is simply using the $(1/2)mv^2$ formula suitable ($(1/2)mv^2$ of after and before)? Or is there a more accurate way?
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Two bodies are stacked on one another with friction. Force applied on bottom body less than maximal friction between bodies. Why do the bodies move?
I'm studying Newton's three laws.
Suppose we have two objects: A and B.
A is on a smooth surface. B is stacked on top of A.
Between A and B there is friction. The static friction coefficient is some ...
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Why a car stops slower when you press the brake pedal fully rather than progressively?
I have always been told that if you press the brake pedal fully and fast it can make the wheels lock themselves, and that you shouldn't do so because it would take longer to stop the car than if you ...
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Is it necessary that friction will produce heat?
If we are moving a block on a rough surface extremely slowly (quasi-statically) with the help of an external horizontal force, then is it the case that no heat will be produced, but the work done by ...
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Does a vehicle turning on a banked road need to turn its wheels?
A vehicle drives in a circle on a track at constant speed at with radius of curvature $\rho$. The vehicle's acceleration is $$a = \upsilon' T + \kappa (\upsilon)^2 N \\ = \kappa (\upsilon)^2 N.$$
The ...
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Can the work done by friction on the whole system be positive?
Suppose there is a plank on a smooth surface and a man is standing on one end of it. The surface of plank is rough. Now the person starts to move towards the other end with some acceleration and the ...
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Velocity and acceleration of sliding blocks on a conveyer belt with friction
If we have a large conveyer belt sliding East with velocity, v, and shove a block moving South at velocity, v, it would be slipping initially. In the reference frame moving along with the sliding ...
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Relationship between kinetic friction and angle of friction
For a body moving on a horizontal surface, is the angle of friction equal to the coefficient of kinetic friction?
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Does extra smoothness between two DIFFERENT substances cause the friction to increase?
I know it happens when the elements on both sides are identical, the more you remove asperities, the more they become like a single substance. But does this happen to the same extent if I take two ...
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Two-body problem in friction [duplicate]
When a block is placed on a slab having coeff. of friction u which is on a frictionless horizontal surface.
Suppose if we apply a force F on upper block which is lesser than the value of limiting ...
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Frictional drag coefficient for flat plate normal to a uniform flow
In the case of a flat plate perpendicular to a uniform flow, it is commonly understood that for high Reynolds numbers, the drag coefficient ($C_D$) is known to be around 2.0. While many references in ...
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Shouldn't acceleration of a car be due to kinetic friction? [closed]
During pure rolling when the car is at a constant velocity the velocity of the bottom part of the tire will be 0. But if we push on the gas we apply an angular acceleration on the tire. So now the ...
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Clarification to questions about friction and cars [closed]
I'm trying to understand how car wheels work. In a perfect world the bottom of the wheel has no velocity. The wheels are in a state of pure rolling, which means there is no static or kinetic friction ...
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A friction paradox
Let's say a mass of 5 kg is kept on a 10 kg block which is kept on the ground.The friction coefficient between the blocks is extremely large say 10 while the friction coefficient is 0 between the 10 ...
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How can I solve this problem about energy conservation according to different frames of reference?
We have two frames of reference: the Earth (E) and a train (T) uniformely moving at velocity u relative to the Earth.
We also have a particle that is initially stationary relative to the train, and is ...
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Can we generate electricity through flying airplanes?
Frictional electricity makes the charges get separated so when the airplanes are running in air at very high speeds, resistance will be created by the air so due to this frictional electricity will be ...
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Solution of Brachistochrone Problem with friction
$\def \b {\mathbf}$
solution of Brachistochrone Problem with friction
from
https://mathworld.wolfram.com/BrachistochroneProblem.html
I found the EL equation (29) and the parametric solution equations $...
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Does air in the atmosphere get friction as a planet rotates?
Does air in the atmosphere suffer friction in some way due solely to the planet's rotation? I mean, if you took a rotating planet with an atmosphere (not being influenced or heated by its star, its ...
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