Friction Definition and 998 Threads

I read friction is the vector sum of the forces acting between the atoms of one surface and another. But the direction of friction is parallel to surface. I don’t get how friction occurs. I will also add the paragraph from my book “resnik” for further clarification. Other question is...

This problem is in a chapter on momentum in the book basic engineering mechanics explained. Help me Mario

Hello, everyone. This problem is easy if you assume that the friction between the blocks and the platform is the maximum possible. Then the normal force is 0. But how can you show that the normal is 0 even when the friction is less than maximum? Thank you for your help.

I have attempted to solve for the velocity by setting the centripetal force (mv2)/r to the normal force pointed to the center of rotation (mg). This approach seems to give the incorrect solution and I am unsure of my misunderstandings.

The answer key is (b) but in my opinion it should be (d) because I think about work done by friction on wheel of car when the car moves. Let say the car moves to the right, then the wheel will rotate clockwise and the direction of friction acting on the wheel by the road will be to the right and...

Suppose you're a point on the floor and a block mass slide pass you. The block mass said " I have friction acting on me during my motion so the mechanical power is friction x my speed". When ask the point on the floor, it said "well, I don't have motion so there is no mechanical power". Yet...

I was looking for a way to calculate the friction arising from the axle and wheel of a standard lab cart. I came across this research paper: https://www.usna.edu/Users/physics/mungan/_files/documents/Publications/PhysEd4.pdf That derived the following equation for the coefficient of rolling...

I need an expert to verify equations about the coefficient of kinetic friction.

Here's a picture of the question: This is a Khan Academy question and although I could just click on hint to find out what the answer is, I think it would be helpful to still ask this here before looking at the answer over there, so that I know what I did wrong. Thank you in advance to anyone...

I get how to solve (a); my method involves finding the net torque about the man's hands and setting it to zero, which can be used to solve for the normal force acting on his feet and the normal force on his hands can be solved using Newton's first law. Then divide by 2 for each to get the normal...

-i had begun by finding the normal force =147 N -then found the force of friction=99.96 N -found the work of friction=-799.68 J after that I am unsure of where to go since I don't have a force applied

I don't know how solve this.. [User has been reminded by the Mentors to show their work on schoolwork problems]

In my teacher’s notes, it said that when the applied force on an object equals the maximum static frictional force, the object begins to move at constant velocity. My question is if both the applied force and the frictional force cancel as they are equal in magnitude, what force accelerates the...

For part 1, I got ## tan \alpha = 1/30 ## ##\alpha = 1.9^{\circ}## ##mgcos(1.9) = 10774N## I'm a little thrown off by the second part. Are we supposed to assume that in the absence of friction, F = N and then substitute F = ma to solve for this?

hey, i was looking for information on friction coefficient of marble on plastic and iron on plastic. if you know these values i'll be very glad! thanks in advance

In the experiment, a cart on an inclined plane of 30 degrees is hooked with the force metre by a line. The line is tension T. It is also subjected to the force of gravity Fg. This makes the cart in static equilibrium. But since the cart is hooked with a line, it does not slide down. The net...

Fn = 53 X 9.81 X cos 22 Fnet = 524 – 53 X 9.81 sin 22 + μ X 53 X 9.81 cos 22

I am confused because according to my solution the disk is already rotating at constant angular velocity. I have written the translational equilibrium on the horizontal and vertical component: ##N_1## and ##f_2## will have a positive horizontal contribution, while ##N_2## and ##f_1## will have a...

It's the body. So there's friction on that plane and there's tension also. $$L=\frac{1}{2}m_1\dot{x}^2+\frac{1}{2}m_2\dot{x}^2-m_2g(l-x)-m_1gx\sin\theta$$ $$f=\mu N=-\mu m_1 g\dot{x}\cos\theta$$ I had found the frictional force's equation from [the...

The solution in my textbook says that for b, us = 0.234. However when I use the formula above I get 0.2364 which I feel like is too far off. Something must have gone wrong... Any help would be much appreciated! Thanks :)

(I drew motion in the opposite direction so the object would rotate trigonometrically but it should be the same thing) I have just finished the Kinetic Energy and Work chapter in my course and this is the last problem from the problem set. I have not worked many problems with the Work-Kinetic...

(a) ##u_{min}=\big(1+\frac{m_2}{m_1}\big)\sqrt{2\mu_k g d}## (b) ##x_f=\sqrt{\frac{2h}{g}\Big(\big(\frac{m_1}{m_1+m_2}u\big)^2-2\mu_k g d\Big)}## Can someone check please?

1) To be in equilibrium, it must be $$\begin{cases}F_{centr}-T=0\\ T-mg=0\end{cases}\Rightarrow F_{centr}=T=mg\Rightarrow m\omega^2 R_0=mg\Rightarrow R_0=\frac{g}{\omega^2}$$ 2) It is intuitive that this equilibrium is unstable but I don't know how to formally prove this. 3) In ##R_0## the...

Imagine a bolted joint with a washer between the bolt and the surface. Assuming the washer is always covered by the bolt head so it's getting a consistent load, does the washer's diameter impact the static friction being imparted on the surface? I see two conflicting ways of viewing this...

I'm willing to build a motorized gimbal head for my camera (something like this: https://www.amazon.com/dp/B01JN5D40A/?tag=pfamazon01-20). If my understanding is correct, given that camera will be well balanced on the platform, the motors would not need to hold the load and only should be...

I am not sure if the explanation below is enough. This is a high school level question. When rubbing occurs between glass and silk, then heat energy is produced which provides the energy needed to free up electrons in outermost orbits of atoms in silk or glass. But silk has very tightly bound...

When fluid is placed between two parallel plates such that one plate is moving and other is stationary, fluid will start flowing. Between plate and the fluid there is viscous friction given by equation: $$ F = -\eta A \frac {dv} {dy} $$ where $ \eta $ is fluid viscosity, $A$ is area of a plate...

Dear colleagues, I am dealing with rope friction and the so-called Capstan equation. Situation: A rope wraps around a cylinder with a wrap angle. It depends on the input force. There are very comprehensive approaches by other colleagues, where the friction value depends on the normal force or...

I am just confused on how to find the normal force/ FN of the first object. My classmates are saying Fgy is the exact same as Fn but I don’t get why Fgy= Fg sin theta Fgy= (20)(9.81) (sin35) Fgy= 112.5 Fgy = FN

Hello, as you can see i am trying to understand conceptually how the tires during turning create a centripetal force. It was explained to me that as we turn the car tires, the tires similar to a ski or a wedge, now want to push the ground to the side and forward. If the ground was loose, this...

Hello, I have a structure with 5 pivot point and those are provided with deep groove ball bearings (see sketch). Calculation for friction losses (deep grove ball bearing): Parameters: - Number of pivot points: 5 - Friction coefficient: 0.0010 - 0.0015 (Reference) Total friction in the...

Attached is the picture of the belt. The angle of wrap seems to be >180 degrees.

However, I can't find any proof on this ? Can someone help to explain this ?

Hello all, I need some help with a problem at statics, friction applied on threads. A threaded screw is given a ("horizontal") force of 100 N at the end of the handle. As the exercise states, they ask to calculate the force which occurs at the tube as well as the force needed to vise handle to...

I drew a free body diagram for the crate. I have normal force going up, weight down, static friction force to the left and the force of the crate sliding to the right. I'm assuming the truck is moving to the left. I have Fnet=0 because the crate is not moving, so the forces are balanced. I...

Two boys are arguing over who gets to play with a toy. The toy has mass 3kg and is at rest on rough horizontal ground with coefficient of friction 0.3. The older boy pulls with a force of 26N at an angle of 39 degree above the horizontal. The younger boy pulls in the opposite direction with a...

This image represents the ramp. The first part is pretty easy. The red part has friction, and the ball rolls down it. The blue part has no friction, and the ball climbs it only owing to the translational kinetic energy that it gained at the bottom of the red ramp, which is only a fraction of...

It's the 10th question. Iam getting the ans for R=90cos34= 74.6 and F=-30.3N, so I get total contact force by using the formula c= sqroot(f^2+R^2)= 80.52N The ans in the textbook is 92.2N. Iam not getting the right ans for coefficient of friction also which is 0.393

A toy car of mass 80g rolls from rest 80cm down a rough slope at an angle of 16 degree to the horizontal. When it hits a rubber barrier at the bottom of the slope it bounces back up the slope with its speed halved and reaches a height of 10 cm. Find the coefficient of friction between the car...

A book of mass 1.3 kg is on a plank of wood which is held at 16 degree to the horizontal. The coefficient of friction between the book and the plank is 0.45. Find the size of the frictional force. Iam getting the ans by using the formula F= coefficient of friction ×R 5.62N but the textbook ans...

It's the 13th question.

A particle slides up a slope at angle 34 degree to the horizontal with coefficient of friction 0.4. It passes a point P on the way up the slope with 3m/s and passes it on the way down the slope with speed 2 m/s. Find the coefficient of friction between the particle and the slope. Coefficient of...

A boy drags a sledge of mass 4kg from rest down a rough slope at an angle of 18 degree to the horizontal. He pulls it with a force of 8N for 3s by a rope that is angled at 10 degree above the parallel down the slope. After 3s the rope becomes detached from the sledge. The coefficient of...

A wooden block of mass 3.5kg is sliding up a rough slope and passes a point A with speed 20m/s. The slope is at 29 degree to the horizontal. The block comes to rest 25m up the slope. Find its speed as it passes point A on the way down. I calculated coefficient of friction = 0.554. U=20m/s v= 0...

A trolley of mass 5 kg is rolling up a rough slope, which is at an angle of 25 degree to the horizontal. The coefficient of friction between the trolley and the slope is 0.4. It passes a point A with speed 12m/s. Find its speed when it passes A on its way back down the slope. So I did F=m×a...

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Take rightwards as positive. There are 2 equations of motion, depending on whether ##\frac {dx} {dt} ## is positive or not. The 2 equations are: ##m\ddot x = -kx \pm \mu mg## My questions about this system: Is this SHM? Possible method to solve for equation of motion: - Solve the 2nd ODE...

A box of mass 50 kg is slowing down from 10 m/s on a rough horizontal ground. The coefficient of friction between the box and the ground is 0.3. To start with, the box is being slowed by a string providing a tension of 25N horizontally. Then the string breaks and the box comes to a halt under...

A snooker ball of mass 0.4kg is struck towards a cushion from 0.8m away with speed 3m/s. The surface of the snooker table has a coefficient of friction of 0.3. When the ball bounces from the cushion its speed is reduced by 20%. Find how far from the cushion it stops.