Friction Definition and 998 Threads

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...

-

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.

A bag of sand of mass 200kg is being winched up a slope of length 10m which is at an angle of 6 degree to the horizontal. The slope is rough and the coefficient of friction is 0.4. The winch provides a force of 1000N parallel to the slope. At the bottom of the slope the bag is moving at 2 m/s...

A gardener is pulling a wheelbarrow of mass 8kg from rest along rough horizontal ground. The coefficient of friction between the wheelbarrow and the ground is 0.6. The gardener provides a force of 50N at an angle of 30 degree above the horizontal as shown in the diagram. a) Find the...

In a factory, a machine picks up a box by clamping it on both sides. The box of mass 4kg is held clamped on both sides by identical clamps with the contacts horizontal. The machine provides a contact force of 50N with each clamp. Find the minimum coefficient of friction between each clamp and...

A chair of mass 6kg is at rest on a rough horizontal floor with coefficient of friction 0.35. It is pulled horizontally by a force of 25N. A boy pushes down on the chair so that the chair is on the point of slipping but remains at rest. Find the force that the boy exerts on the chair.

A box of mass 20 kg is at rest on a rough horizontal ground. Find the magnitude of the total contact force in each of the cases. a) The box is pulled horizontally to the right by a force of 40N b) the box is pushed to the left by a force of 50N at 15 degree above the horizontal . c) the box is...

Hi, actually it's not my homework, I'm just practicing some academic problems after a long break but it seems that I should post this here anyway. Here's a scheme of the problem that I want to solve: The task is to calculate minimum force ##P## for the system to stay in equilibrium. And...

My understanding of static friction is that it is a resistive force in response to an applied force. I recently read the following example. A rope of uniform density, length L, is fastened to a plane with incline angle “theta” along its length. The question asks for the tension at the top of...

if the Work done by friction is -4.73 for object #1 but the work done by friction for object #2 is -4.63, in which scenario is the Work greater - the signs are throwing me off. Also, let's say the initial elastic energy of a ball is 5 and its final energy is 0.27 (scenario #1) vs its final...

So I have questions on two separate questions. The first question is about the fbd of the plate attached to the pin. How can there be an Ax since there’s no other force in the horizontal direction wouldn’t the plate start moving on the x-direction due to imbalanced forces. Second question about...

Confused how to approach problem after making a free body diagram and finding the length of the inclined plane

This was the answer key provided: My questions are the following: if the force required for rotational equilibrium is more than the limiting static friction, then the body will rotate aka slip over the surface. When it slips, the frictional force will be kinetic and not static, right? If I...

In this part of the lab we pushed a block on a flat table and let it slide until it stopped. So it is decelerating with no force being applied to it while moving. In this case acceleration is negative. The only force acting on it is kinetic friction. Therefore I have come up with the following...

Hello Everyone, I'm working on a future mechanical structure with a rotating shaft. In this project, I should be able to control the resistance on the shaft but instead of adding some extra weights on the shaft to increase inertia, I don't have any ideas. Does anyone have an idea of simple...

A 7.80 g bullet is initially moving at 500 m/s just before it penetrates a block of solid rubber to a depth of 4.50 cm. (a)What is the magnitude of the average frictional force (in N) that is exerted on the bullet while it is moving through the block of solid rubber? Use work and energy...

I have no clue how to do this, so I did my best guess of it. Friction is μN, N being the normal force. The normal force when it is in contract with the pole should be V2/R, R being the radius of the pole. So ΔT = μV2/R The answer provided is μTΔθ

Hi, We have a cylinder held by a rope . The rope holds it around its lower half. If the center of mass of the cylinder is not in the middle, but towards a side, a distance "a". How does this offset affect to the friction on the rope? or How big does "a" have to be so the cylinder starts...

I have attempted this problem by solving for the normal force. (16.73)(9.8)-51.25(sin)(49.1). I tried to work that out but it was incorrect because apparently the vertical force is zero. Could I get an explanation on what that means and where I should start?

So first I made an equation representing the forces Fnet=kx-12.8v a=1/m(kx-12.8v). Now I am not really sure how to get w from this. I could argue the mass is at its max amplitude when a=0, but that wouldn't help me find w. If I say x(t)=kx-12.8v, then 1/m would be w^2, but this isn't right...

Considering an stopped object in a horizontal plane, the frictional force between the object and the plane would be the product of the friction coefficient (static or kinetic if there was movement between the surfaces) by normal. Since the normal in this case would be given by N (vector) = - mg...

https://www.physicsforums.com/attachments/277763

I have a question about friction between pulley and rope? Does anyone know how to calculate friction between pulley and rope I enclosed an example picture Thank you!

As far as I’ve gathered, for a system to rotate there has to be some static friction acting upon it and dynamic friction can be zero. But now I’m a bit confused about this as we completely disregarded static friction in some tasks where a system was rotating. So was my original assumption wrong...

Hi, I am working on a project regarding the friction drive on bicycles. I would like to design an assembly which has to be compact enough, and has to be able to produce torque that will move the bicycle from a stationary position, but as it turns out with my calculations torque required is...

Solution in 2ed manual: Solution in 1ed manual: Could someone explain why the work done by friction is multiplied by 2? I get that the distance traveled by the block in one cycle is greater than ##x_f+x_i##, but why is the coefficient two?

Summary:: I am not sure about how can I write an appropriate equation to a question which include friction force and initial velocity. I came across a question that I am not sure how to write an equation.In the question, there is an object of mass m that is thrown into spring at v initial...

First calculated non conservative work from friction using Ff=umg. Non conservative work was -8.82. Initial kinetic energy, 1/2mv^2, was 136.89. Change in potential energy, 1/2k(x)^2, was 8.1216. Ekf-Eki+Change Ep=Work NC Ekf=W NC+Eki-change Ep =-8.82+136.89-8.1216=119.9484 Ekf=1/2mv^2...

A force P is exerted on two articulated rods that are connected to two small blocks A and B. Both blocks have the same weight G. The magnitude of the force P = 1.26 G. The static friction coefficient between the blocks and the ground is 0.3. The mass of the rods may be neglected. It can be...

Would we use the mass of the bucket and pucks to get a higher acceleration? I don't understand the use of the pucks in this question? How would the three laws relate to this?

Please scroll-down to Q50: https://www.undergraduate.study.cam.ac.uk/files/publications/engineering_s1_qp_2017.pdf The correct answer is 'B', or 'mgsin(Θ)'. I put 'E', or 'μmgcos(Θ)'. There are unofficial worked solutions which I have been referring to when I have attempted the question and...

re: https://www.physicsforums.com/threads/is-it-possible-to-solve-for-t.996132/post-6421205 https://www.physicsforums.com/threads/is-it-possible-to-solve-for-t.996132/post-6421230 Would it be possible to find t and r via the exact same equations as found in posts #4 and #10, and then find the...

My first question is actually, what happens when any two objects get near each other? This question is often phrased as "Why can't you really touch anything?" or "Why can't you walk through walls?" I have heard two answers: 1. the repulsion between electrons 2. the Pauli exclusion principle...

In the attachment I am supposed to calculate the maximum frictional force of a block on a 35 degree angle incline (that is the point at which the force acting opposite frictional force is highest) I make it out to be sin(35)*120N = 69N but the book says 675N and it gives it as...

Hello! So the way I have tried to solve this problem is the following;Since it is an inclined plane and the cofficient of static friction is known, getting to the angle at which the box starts sliding is the following ##μH = \frac {sin (\alpha)} {cos(\alpha)} = μH = tan(\alpha) ## ## \alpha =...

What I know is that the force of friction and the normal force are the components of a contact force. So force of friction is related to the contact force. Friction is also related to the normal force by equation ##F_t= μ\cdot N##. In this case (because the block is not moving) N=0 and...

I'm a little confused about this question because I think the braking deceleration probably takes into account the braking system of the vehicle as well as the power of the motor. I don't understand how a car could actually brake without the "friction between the mechanical components of the...

So after trying to calculate the horizontal forces to solve it: f + Wx(gravity force component of x) - Fy ( the Force that is supposedly giving the the acceleration) = 0 It got to me that the question said "plane has the acceleration" is that even possible? Unless the plane is another object...

Torque on driver T = 2300N x .2m = 460Nm Torque on drum T=2300N x .6m T = 1380Nm Not sure how to calculate friction force on these...Do we have to assume a contact angle of 180 degrees if nothing is given or is that even required? Not sure what a free body diagram would look like for this.