Questions tagged [friction]

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

Filter by
Sorted by
Tagged with
0
votes
2answers
25 views

The reason behind circular motion of vehicles

In all the textbooks and internet resources that I've ever read , most of them explains role if friction in circular motion of an object (let's says a cycle), from the frame of the cyclist i.e. with ...
0
votes
2answers
30 views

Friction and Circular Motion

In circular motion, it is said that the friction acts towards the centre of the circular path. But friction opposes tendency of relative motion and since the velocity of the body(in circular motion) ...
1
vote
0answers
22 views

Why do we consider the viscous force to be tangential?

Is it that since it is a friction force, it needs to be tangential as other friction forces like kinetic friction and static friction forces are?
7
votes
8answers
754 views

Physical Interpretation of an Overdamped Pendulum

Consider a damped pendulum whose equation of motion is given in general by $$m\ddot{x}=-\mu\dot{x}-kx$$ where $\mu,k>0$ Rewrite this equation as $$\ddot{x}+2\gamma\dot{x}+\omega^2x=0,$$ where $...
-2
votes
0answers
43 views

A tough integration based problem [on hold]

A massless rope is tossed over a wooden dowel of radius $r$ in order to lift a heavy object of weight $W$ off the floor. The coefficient of sliding friction between the rope and the dowel is $\mu$. ...
2
votes
0answers
41 views

How does friction cause a spinning top to fall?

I am wondering how friction can create a torque to change the angular momentum and cause a spinning top to tilt, like in the diagram of a close up of the rounded tip of a top while the angular ...
3
votes
1answer
70 views

Why can't $U=b\mathbf{v} \cdot \mathbf{r}$ be considered a potential for the drag force ${\bf F}=-b {\bf v}$?

Consider the function $U(\mathbf{r},\dot{\mathbf{r}})=b\mathbf{r} \cdot \mathbf{v}=bx\dot{x}+by\dot{y}+bz\dot{z}$, where $b$ is the drag coefficient. Why can't this be considered as a potential energy ...
3
votes
2answers
89 views

Why can I not draw with a pencil on my hand, while a pen works perfectly?

As far as my understanding goes, a pencil is able to write on paper, because of friction, bits of graphite re scrapped of from the lead. But then why is it that it doesn't work on my hand?? A hand is ...
-1
votes
1answer
28 views

$\mu_k$ of surface from experimental vs theoretical acceleration [on hold]

I have an air track at a slight angle with a glider. Final velocity is determined, and from that a is calculated, and from a, I have approximated g. I am trying to find $\mu_{k}$ between the track and ...
2
votes
2answers
68 views

Objects traveling through water

If an object travels through water fast enough, can it create enough friction to burn? I'm sure a human could get to the point where their skin would become red the same as a belly flop. But what ...
0
votes
0answers
24 views

Free body diagram [duplicate]

I was reading about the ABS brakes and the articles say the wheels don't slide on the floor and the tire friction is static. but what would the force diagram of a tire look like under ABS? Wouldn't ...
1
vote
2answers
93 views

Why does a car which decelerates slowly on a icy road not slip but a car which decelerates quickly does?

Why is it that braking slowly on an icy road is safer than braking quickly. Intuitively it makes sense but what is the logic?
0
votes
1answer
44 views

Find coefficient of friction [closed]

A plank P and a block Q are arranged by keeping block Q on the extreme left of plank P. The surface between P and Q has friction whereas coefficient of friction between plank P and ground is zero. ...
0
votes
2answers
45 views

How is the angle same in friction force? [closed]

How is the angle $\theta$ of the plane and between the $mg$ (attraction due to gravity) and component of $mg$ is same? In the figure $\theta$ between the $mg$ and its component $$mg\cos\theta$$ is ...
-1
votes
1answer
44 views

Friction and energy conservation [closed]

A curved surface is shown in figure . The portion BCD is free of friction. There are three spherical balls of identical radii and masses. Balls are released from rest one by one from A which is at a ...
1
vote
1answer
39 views

Work done by friction on an inclined plane

A rough inclined plane is placed on a cart moving with a constant velocity u on horizontal ground. A block of mass M rests on the incline. Is any work done by force of friction between the block and ...
-1
votes
1answer
41 views

Is rolling resistance really this low for moving a locomotive engine? [closed]

So today I was working on a simple physics problem which says to compute the rolling resistance, necessary to roll the wheel along the rail. Here is the relevant data about the problem: A steel wheel ...
0
votes
2answers
99 views

Isn't friction on an incline coefficient of friction times the Reactional force?

Question - "As shown in figure a body of mass 1 kg is shifted from A to D on inclined planes by applying a force slowly such that the block is always in contact with the plane surfaces. ...
0
votes
0answers
26 views

Maximum acceleration on a turn

The question $\\$ Suppose a car enters a turn with an initial speed $\vec{v_1}$, and comes out with a final speed $\vec{v_2}$ perpendicular to the direction of $\vec{v_1}$. The driver does everything ...
5
votes
6answers
633 views

Why does the friction act on the inward direction when a car makes a turn on a level road?

I tried looking this question up online but am left a little confused with all the answers, and the diagrams. When a tire of a car negotiates a turn in the road, there exists friction which is ...
0
votes
1answer
28 views

What's the “cause” of damping coeff. in springs?

What's the "cause" of damping coeff. in springs? Air resistance, friction?
2
votes
2answers
48 views

What is the exact role of friction in rolling without slipping?

When an object rolls along a plane, we say that for the object to roll without slipping, the velocity of the center of mass must be equal to angular velocity times radius, so that at the point of ...
1
vote
0answers
48 views

Derivation of equation of motion for mechanical seismograph

Consider a simple seismograph consisting of a mass $M$ hung from a spring on a rigid framework attached to the earth, as shown in the picture. The motion of the mass is apparently described by the ...
0
votes
3answers
91 views

What helps us carry things around? [closed]

Say I move from point A to point B. I carry an apple in my hand. What causes the apple to move from point A to B? In other words, what force is responsible for keeping the apple stuck to my hand and ...
23
votes
6answers
7k views

What force enables us to walk? Friction or normal reaction?

I know that this question has been asked here before, but I am a little bit confused with all the answers. So when we move, we apply force on the ground in the backward direction. So, is the ground ...
0
votes
3answers
56 views

Rolling without slipping forward force

I'm studying rolling without slipping, I want to find the net force making a wheel go forward when applying a torque about the axle of the wheel. In this page https://www.school-for-champions.com/...
0
votes
1answer
50 views

Friction in opposite directions on a rotating disc [closed]

A disc with radius R rotates at constant angular velocity $ω$. At time $t=0$ a person steps onto the disc at point $A$ and moves at constant velocity $V$ (with respect to the rotating framework) to ...
1
vote
2answers
76 views

Coefficient of friction in pulley system

EDIT: Picture doesn't show the mass of $\mathrm A$. It is $60\ \mathrm{kg}$. My attempt: I placed my coordinate system with $x$-axis parallel to the ramp surface and $y$-axis parallel to the normal ...
0
votes
1answer
50 views

How does the static friction $\vec{F_{1,2}}$ and $\vec{F_{2,1}}$ generate here?

How does the static friction $\vec{F_{1,2}}$ and $\vec{F_{2,1}}$ generate here? I am confusing with $\vec{F_{1,2}}$ and $\vec{F_{2,1}}$ My understanding from the video:- If we push the block (2) with ...
1
vote
2answers
59 views

Question related to maximum static friction and minimum $\mu_s$

I think I have the right formulas the answer the following question, but there is something conceptual that is throwing me off (see end of question). A body with mass $m$ is located on a slope with ...
0
votes
1answer
18 views

How do I know that $\mu_k$ independent of velocity and the area of contact?

Doubts:- Although he is stating that till now there is no effective model to explain kinetic friction. (1)Why Kinetic friction is independent of the contact area of the body with the surface? (2)Why ...
0
votes
3answers
48 views

Inclined plane with friction and a spring

I am given a body with a mass of 1 kg that slides at a constant speed down an inclined plane with an angle of 30 degrees. At the end of the incline there is a spring with a spring constant of 500 N/m. ...
1
vote
0answers
33 views

Is it possible to model a locomotive capable of going 0-60 in 60 secs with $\sum F=F_{engine}+\mu_{rolling}mgv$?

The problem of just considering engine force and rolling friction $$\sum F=ma=F_{engine}+\mu_{rolling}mgv$$ is that when you solve for velocity like $$\dot v=\frac Fm-\mu gv$$ with initial ...
0
votes
2answers
40 views

Static friction in a slope and two boxes problem

The context: Calculate the string tension in the situation where two boxes are stacked on a slope and moving with uniform velocity, given that the kinetic friction coefficient between the heavier (...
0
votes
2answers
64 views

Vertical component of friction

If we have a car of mass $m$ sliding around a banked curve of angle $\phi$ with some coefficent of friction ${\mu}$, then the normal force will be $$Ncos\phi= mg + {\mu}F_{g}\sin\phi$$ But this ...
0
votes
1answer
49 views

Help with the problem of moving two fingers along a yardstick

The following problem is taken from an MIT homework assignment: Hold a yardstick horizontally on your index fingers and slide your fingers together smoothly. The stick slides first on one finger, ...
0
votes
4answers
50 views

Will friction on tyres due to road still act if the vehicle is moving with constant velocity?

A car moves with the help of friction from ground...while analyzing a car moving with constant velocity..should one consider the frictional force acting at the contact point of road and wheel? If ...
1
vote
0answers
39 views

Friction at high speeds

I am reading a book which mentions that frictional force is not exactly proportional to the normal force at high speeds. Quoting: Once the bodies slip on each other frictional force is, $kN$. This ...
0
votes
1answer
57 views

Is it possible to find $\mathbf{v}$ explicitly when $\mathbf{F}$ varies with $\mathbf{v}$?

I have the following problem (NO, this is not to ask for a solution to this problem). A block is placed on a plane inclined at an angle $\theta$. The coefficient of friction between the block and ...
0
votes
0answers
15 views

Effect of Particle Size on Angle of Repose for Sand

I have been doing research into how the size of granular material affects the angle of repose. There have been several conflicting results on this topic. Several papers cite that the angle of repose ...
2
votes
1answer
47 views

Conservation of energy with friction on a pool ball

I have a problem where I am given the mass $m$, radius $r$ and friction $\mu$ between a pool ball and table. The ball is not initially moving but at $t=0$ is struck by an impulse $$p=\int_{-\epsilon}^...
0
votes
2answers
54 views

Laws of motion (friction on rough inclined plane)

For equilibrium of a body on an inclined plane of inclination 45°. The coefficient of static friction will be 1) greater than one. Why? My question is why do we use greater than sign instead of ...
1
vote
1answer
31 views

Discontinuity in fluid friction as a function of Reynolds number

I have observed a discontinuity in the Fanning friction factor chart, at around Reynold's number of 2000. I know that this is the region where laminar flow changes to turbulent flow, but a ...
0
votes
1answer
37 views

Work done by static friction in Rolling

In rolling without slipping, I understand that the velocity of the point where static friction with the ground is 0, and therefore static friction cannot do work. However, from newtons laws, an object ...
3
votes
6answers
169 views

Does the force of friction helps us to accelerate while running? [closed]

The question is to find the correct statement: Cause of increase in kinetic energy while running is due to the work done by friction force without which he cannot run. OR Cause of increase in kinetic ...
1
vote
1answer
29 views

Are constraint relations valid on friction [closed]

I was doing a question in Newton's laws of motion where I came across this question . The question said there was same frictional coefficient between all surfaces and there is no acceleration of the ...
0
votes
5answers
119 views

What force stops a car?

I've been doing physics problems regarding cars for a while. I understand that there is a static friction (which appears when the wheel is rolling) and kinetic friction (which appears when the wheel ...
0
votes
1answer
44 views

Braking systems on cars

I thought of a maths problem for myself to solve, as it seemed like a good problem to try to get my head around. My issue is that I got stuck at the first hurdle. I was reading up about the braking ...
18
votes
5answers
5k views

Does friction always oppose motion?

Recently I had the following misconceptions: Static friction always opposes the motion of body. The force of friction cannot initiate motion in a body. Now I came to know that my understanding was ...
0
votes
2answers
72 views

Why does a ball keep rolling?

When a rigid ball rolls on a plane with no other forces, it is known that no friction applies and the ball keeps rolling. I was asked if this $F_{\text{friction}}=0\,$ can be derived from the usual ...