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

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6
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5answers
176 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
votes
1answer
33 views

Understanding the constraint of tension with a rigid body

I want to know why doesn't $T_1 = T_2$? I think its probably because of the Pulley but still aren't the Tensions Equal but opposite in direction.
1
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2answers
58 views

Sliding along a circular hoop: work done by friction

Assume a point object of mass $m$ slides along a hoop of radius $R$, starting from a position which makes 90 degrees with the line of radius connecting the center and the ground. Let the coefficient ...
1
vote
1answer
153 views

Compression vs. Friction - what happens when space objects enter earth's atmosphere

When reading about what happens when cosmic debris enters the earth's atmosphere, some sources say friction, others say compression. For example: On space.com it says: Meteor showers occur when ...
0
votes
2answers
162 views

Finding equation of motion for a two mass one spring system

I'm trying to find the equation of motion for the system below. As you see, there is a trailer connected to a car with a spring. There are a "b.v" force where b representing a coefficient of ...
0
votes
1answer
94 views

Calculate the change in mechanical energy for a system in presence of friction [closed]

The two masses in the figure are released from rest. after the $3$ kg mass has fallen $1.5$ m, it's moving with speed of $3.8$ m/sec. what is the change in mechanical energy done on the system during ...
0
votes
4answers
149 views

Driving on the moon

I think that a car which is applying its max force on Earth stops accelerating (as in, stops increasing in speed) because of air resistance. But on the moon there is none so I think the car would ...
3
votes
2answers
98 views

Dissipative forces and reversible processes

A book that I have contains the following lines: For a process to be reversible, the dissipative forces such as viscosity and friction should be absent. My question is why?
0
votes
1answer
102 views

Max Acceleration on an incline? (2010 F=ma #8) [closed]

(From 2010 F=ma, #8) A car attempts to accelerate up a hill at an angle θ to the horizontal. The coefficient of static friction between the tires and the hill is µ > tan θ. What is the maximum ...
3
votes
3answers
76 views

Why is the rod moving to and from?

These are tow pulleys, and a plastic plank is placed above them which can slide freely. The plank has uniform density and it touches both the pulleys. Both pulleys are placed on the same plane, and ...
1
vote
1answer
76 views

Does more surface area mean more traction?

I came across this question when considering new vehicle tires in a snowy environment. It appears that big off-road tires have very deep treads which greatly increase the surface area of the tire. ...
1
vote
1answer
30 views

How far will the key slide? [closed]

A person tosses his car keys on a shelf with an initial velocity of $2\:\mathrm{m/s}$. How far will the keys slide if the coefficient of kinetic friction between the surfaces is $0.3$? How would you ...
1
vote
0answers
28 views

Friction between $n$ surfaces? [closed]

Since two weeks ago, I have been working on a project where $n$ things are overlap together (with different coefficients of friction) for getting the force that's need for pulling them apart. Could ...
12
votes
1answer
285 views

Flipping a deck of cards: why do the cards cluster?

First let me describe what I mean by flipping a deck of cards. Fan a deck out, take the card on one side, flip it - then, much like a string of dominos, the rest of the cards are flipped and end up ...
0
votes
1answer
146 views

How are unbalanced forces even possible, given Newton's 3rd law? [duplicate]

The notion of an unbalanced force seems to contradict Newton's third law, entirely. For instance, apparently, if you push a rock, then an unequal force is being applied in the opposite direction with ...
1
vote
0answers
132 views

Pulley system on a double inclined plane [closed]

(Lets say, say static friction is $\mu_s$, and kinetic friction is $\mu_k$ for both of them) What is the detailed definition of static friction according to this picture? When the system starts to ...
0
votes
3answers
106 views

A moving bus suddenly stops. Is its momentum destroyed?

Absolutely not but how does momentum transfer to surrounding (ground, air particles)?
1
vote
2answers
44 views

If two very small and smooth particles collide at perfect right angles, is there friction?

If two perfectly round particles collide at perfect right angles, is there friction between them? If so, Is the friction in the form of heat (average kinetic motion), because if it is, where is this ...
1
vote
1answer
62 views

Rotational equilibrium Paradox

A block of mass M and height h is moving on a rough surface of coifficent of friction 0.5 .The block is moving with a velocity v at some instant. if we balance the torque due to frictional force and ...
2
votes
0answers
33 views

How fast does water have to be moving for it to gain a lot of heat? [duplicate]

A random question popped into my head a few minutes ago: objects, when moving fast enough, start to get resistance from the air. Since there is friction between the air and the object [water], there ...
0
votes
1answer
57 views

Inclined plane problem [closed]

This is the problem question from my textbook. My questions are concerning some formulas related to this problem. The force of friction is obviously down the plane. My initial question is: $F_{...
0
votes
1answer
75 views

Newton's 3rd law applied to friction

I'm confused about how Newton's 3rd law applies to friction. If you slid an object across a table then the particles you are sliding against would exert the same force back, but wouldn`t this mean ...
0
votes
1answer
46 views

Will loss of contact with the ground remove friction forces?

If we suppose that one object is losing contact from the floor, let's say the trajectory of this object is a semisphere, then in this instantaneous time just before the contact is loss will make the ...
0
votes
1answer
196 views

Spring Constant of a Slingshot

So we have a elastic slingshot which slides a block across the floor until coming to a stop but we've been facing a couple difficulties in determining our spring constant. We have a table of forces ...
0
votes
0answers
35 views

How to derive friction laws?

How do I derive the laws: $$F_s = \mu_s N, F_k = \mu_k N$$ For static and kinetic friction? It was one of the very first things I was ever taught in a physics lesson, and yet to this day I still don'...
12
votes
5answers
3k views

Is there any friction between wheel and road?

Human beings invented the wheel to get rid of the friction between the wheel and the road. But were we able to reduce it to zero? Is there any residual friction? This question is about only the ...
0
votes
1answer
149 views

Rolling Friction Problem

The handbrake of a vehicle of mass $1.5\ \mathrm{tonnes}$ completely fails while it is parked on a $30^\circ$ slope. It rolls $20\ \mathrm{m}$ down the slope before colliding with, and locking on to, ...
1
vote
1answer
36 views

Does an object reversing direction experience static friction?

I know that there is kinetic friction, experienced by an object in motion, and static friction, experienced by a stationary object put into motion. Take an object that is pushed, this push makes the ...
0
votes
0answers
58 views

Stokes' law and settling particle speed

What are the forces that are exerted when a particle is dragged by air flow in a tube and settles within some distance? Does Stokes' law calculate the net force, taking into consideration of all these ...
-1
votes
1answer
35 views

How does static friction provide centripetal acceleration? [duplicate]

While reading about the motion of a car on a level road, I read that static friction provides centripetal acceleration? Please explain as simple as possible.
1
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0answers
135 views

Friction in Lagrangian formulation

We know the Lagrange equations are: $$\frac{\partial \mathcal{L}}{\partial q_i}-\frac{d}{dt}\left(\frac{\partial \mathcal{L}}{\partial \dot{q_i}}\right)=0.$$ Then, when we add friction in there, we ...
0
votes
1answer
20 views

Why is the friction vector resolved even though the inclined plane is the reference plane?

I do not understand why the frictional force is resolved even though it is already on the reference x-axis. Asked this question to college teacher and got reply,"I will do it later" and later never ...
-1
votes
2answers
386 views

Work done by Friction. Can it be positive or zero?

The work done by frictional force is negative as it opposes the relative motion? Please explain when will the work done by friction be (i) zero (ii) positive ?
1
vote
1answer
61 views

Where to hit the pool ball such that it satisfies the given condition? [closed]

The question Where to hit the ball in such a way that after covering a certain distance it rolls back? You are given a pool ball and you have to find where to hit it such that it rolls back after ...
1
vote
2answers
337 views

How does this spool have an angular acceleration opposite to its acceleration?

Consider this spool. It rests on a rough horizontal force. The green lines are the ground, and a line parallel to the ground. The spool is pulled without sliding by the thread (with tension T), with ...
2
votes
1answer
47 views

Friction in a fluid

when an object is moving in a fluid(air for example), the air will resist the object's movement: molecules of the air will collide with the surface of the object (no slip condition) and then we will ...
0
votes
0answers
44 views

Pulley Friction

Why is the frictional force of a rotating pulley 0? For example, consider two masses and a string that links those masses passing through a pulley. Why do we not account for the frictional force of ...
2
votes
1answer
67 views

Why does a top spin so well?

I know that the force of friction does not depend on surface area, but then why does a top spin better on a point rather than a region of larger surface area. For example, if I spin a top on it's ...
2
votes
3answers
450 views

What is the relationship between rolling resistance and velocity?

I'm a games programmer, trying to write a simple car physics simulation. I'm aware that a car travelling in a straight line will exert a traction force that drives it forwards (by turning the wheels ...
1
vote
3answers
694 views

When does normal force equal to $mg$?

Can someone once and for all explain when does normal force equal to mg? I know for sure that when there is no friction, normal force will be equal to mg. But, i encountered some questions when there ...
1
vote
2answers
70 views

Friction in driving car

We know friction helps in driving car, does this mean car can move faster on rough surfaces ? Since coefficient of friction is more on rough surfaces
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2answers
209 views

Best angle to pull an object

I'm fairly new to physics (high school) but really enjoy. I recently came across a problem of my own that I tried to solve: what is the best angle to pull an object at? I derived $F=F\cos \theta-\mu ...
0
votes
2answers
61 views

Finding Friction and Coefficient of Friction Force? [closed]

A $65\,\mathrm{kg}$ object slides down a $30^\circ$ slope at a constant speed. Air resistance is negligible. Find the coefficient of friction and force of friction. The normal force equals $F_\text{...
0
votes
2answers
42 views

Friction in an ascending elevator

When a lift moves up the normal reaction,R is greater than the weight,mg,producing common acceleration mf such that R-mg=mf Friction,F=coefficient of friction ×R.In case of an ascending lift R is ...
1
vote
1answer
107 views

Measure ball's acceleration down inclined plane

If I am asked to devise an experiment to find an expression for the acceleration of a uniform sphere (ball bearing) rolling down an inclined plane, as a function of the angle of incline. Hence deduce ...
0
votes
2answers
126 views

Does really a spring compresses placed between two blocks when one block is given force on a frictionless surface?

When Spring is placed between two bodies on a frictionless surface it gets compressed when one block is given kinetic energy as told by my physics teacher. But it should not compress as there's no ...
0
votes
3answers
195 views

Sliding and rolling friction

I heard that friction depends only on the normal force but not on the contact area. Let's take a cube and a sphere which are of same weight (then normal force will also same ) but the force needed to ...
0
votes
0answers
38 views

Friction between needle and bearing

I have a question about friction and its effect on materials. Please forgive my long description of the problem. I have made a Device that is designed to slowly oscillate a magnetically suspended ...
0
votes
1answer
43 views

Calculating constant velocity from friction [closed]

I'm unsure if my Book is wrong. Either way, we send a pinball through a cylinder filled with oil, the forces that apply are. Fpinball = 15,8 ∙ 10^−6 ∙ 9,82 = 5,69 ∙ 10^−5N Foil = 𝜌 ∙ 𝑔 ∙ 𝑉 = 0,...
8
votes
2answers
352 views

A false proof of drag force being conservative

Consider a particle moving along some trajectory in the $x$-$y$ plane, in a viscous medium. Then its equation of motion is given by: $$\mathbf{F}_d = - b \mathbf{v} .$$ it's well-known from the ...