Friction Definition and 998 Threads

Homework Statement The question is as follows: A 50kg ice skater is gliding along the ice, heading due north at 4.0m/s. The ice has a small coefficient of static friction, to prevent the skater from slipping sideways, but kinetic friction =0. Suddenly, a wind from the northeast exerts a force...

Homework Statement A roller coaster reaches the top of the steepest hill with a speed of 7.0 km/h. It then descends the hill, which is at an average angle of 43° below horizontal and is 46.0 m long. What will its speed be when it reaches the bottom? Assume the coefficient of kinetic Friction...

Homework Statement A crate is being transported on a flatbed truck. The coefficient of static friction between the crate and the bed is 0.470. What is the minimum stopping distance if the truck, traveling at 70 km/h, is to decelerate uniformly and the crate is not to slide forward on the bed...

Homework Statement A worker is going to attempt to pull a 90-kg box across a level floor by a rope that makes an angle of 35° with the floor. The tension in the rope is gradually increased until the box just starts to move. If the coefficient of kinetic friction is 0.36 and the coefficient of...

Could anybody explain what happens at the molecular level when one of the two bodies in a contact starts moving w.r.t other, i mean in this process what causes kinetics friction force, i tried myself to think of it but i could not come up with any, so please help me.

At a force of 40N, the body moves along a horizontal surface with an acceleration of 2m/s^2 and under the action of 50N with an acceleration of 3m/s^2. What is the mass of the body? F1 = 40N a1 = 2m/s^2 F2 = 50N a2 = 3m/s^2 _____________ m=? 2. Homework Equations As there's no...

Homework Statement I am referring to this thread and question: https://www.physicsforums.com/threads/rotation-of-a-spool-about-rough-ground.295666/ Here is the problem, restated: Homework Equations ##\tau_{net} = I\alpha## ##\tau = Frsin(\theta)## ##F_{net} = Ma_{cm}## ##\alpha = a_{cm} /...

Here is problem I quickly made up: Suppose there is a ramp with a height of 6 meters and length of 12 meters. A block of 5 kg is pushed up to the top of the ramp with a constant velocity. The force of friction is 15 N. Here's the confusion: By using the non-conservative force work energy...

I have been thinking about the Higgs field and how things interacts with it. I thought about why photons for example does not interact with it while quarks does. It could be because of the size and if when a particle is a certain size it will interact with the Higgs bosons and then slow down and...

How would I calculate the frictional torque of rotating an axle with a square cross section? The axles that I’m using to drive a gear box are rectangular instead of cylindrical like normal axles, so I’m trying to figure out how much more a motor has to work to turn a square axle than it does to...

Homework Statement A grocery cart with mass of 19.3 kg is pushed at constant speed along an aisle by a shopper who exerts a force of 13.1 N on the cart at an angle of 18.3 from the horizontal. The aisle is 15.1 m long. The coefficient of friction is 0.0658. Find the work done on the cart by...

Homework Statement A 2.79-kg block is placed on a rough surface inclined at 28.1°. The block is launched at a speed of 3.87 m/s up the incline, and comes to rest after sliding 0.969 m up the incline. Find the coefficient of kinetic friction between the block and the incline. Homework...

Homework Statement I don’t have a specific problem to solve, and I’m not sure I would be able to correctly find one, but I need to know how to solve a harmonic Oscilator problem with Friction. I believe I should be starting with F = -kx -Ff, and that I will be given some information about the...

A 50 kg box rests on the floor. The coefficients of static and kinetic friction are 0.70 and 0.50, respectively. a.) What is the minimum force required to start the box sliding from rest? b.) After the box starts sliding, the person continues to maintain that force. What is the...

A car traveling at 97 km/h can stop in 48 m on a level road a.) Determine the acceleration of the car b.) Determine the coefficient of friction between the tires and the road Homework Equations : Vf^2=Vo^2 +2aΔx μ=Ff/mg[/B] 3. I have part A, I got -7.53 m/s^2, but I can't seem to...

https://curiosity.com/topics/a-mystery-of-einsteins-relativity-has-been-explained-using-classical-physics-curiosity?utm_source=androidapp If anybody understands what the author is trying to say, kindly elaborate. I haven't read the paper

Homework Statement What is the minimum work needed to push a 1000-kg car 300 m up a 17.5 degree incline? A. Ignore friction B. Assume the coefficient of friction is 0.25 Homework Equations W = F*d Net force = ma The Attempt at a Solution At first I did: Work = F*300*cos17.6 but I later...

Hello, I have a project that requires me to calculate break force friction of a piston seal on the cylinder wall. I have a double acting cylinder at very low pressure, 3.5" diameter bore, one side of the piston is air, the other side is water. What seal type, seal compression, lubrication and...

Homework Statement I have a homework assignment that requires me to use the coefficient of static and kinetic friction for rubber on wood. I cannot locate this value anywhere so far. Homework Equations None. The Attempt at a Solution I have searched and searched and I cannot find the...

Homework Statement Kerry is pulling a 156-kg sled along a snowy, horizontal path with a 620-N force directed at an angle of 29.0° above the ground. He pulls the sled over a distance of 26.0 m, and the coefficient of kinetic friction between the sled and the ground is 0.0622. I need to find the...

The question that puzzled me during lecture! : A block is pushed so that it moves distance L up a ramp (incline angle q ) at constant speed. If there is friction, the magnitude of the work done on the block by friction…(ramp is up and leftwards) A. is mgsinqL. B. is less...

Homework Statement In the question, a person is pulling a 156 kg sled up a hill. A 620 N force is used to pull the sled up the hill that has an angle of 29° with the horizontal. The sled is pulled a distance of 26 m, and the kinetic friction coefficient is 0.0622. The system has been defined as...

I found a problem and I'm having one question, it goes like this: A box of 5 kg is being dragged across the floor with a horizontal force of 40 N. If it starts at rest and it begins to accelerate at 3 m/s2 (constant acceleration), find: A) The coefficient of kinetic friction B) Supposing that...

Homework Statement An object of mass m=2 kg slides down on a track from a height of h = 10 m. The track is frictionless except the horizontal range between the points A and B. The friction force is constant between A and B. What is the speed of the object at point B if the magnitude of the...

1. Homework Statement You have two masses moving across a frictionless surface, yet there is friction between the two masses. Mass 2 is on top of Mass 1 A force is applied to m1 which causes It to accelerate at 6 m/s2 and the friction between the two masses causes m2 to accelerate at 4 m/s2...

Homework Statement There is a mass on incline surface that is acted by foces. μ=0.8 m=2 kg θ=30° g=10 m/s^2 ##F_N##= normal force ##F_F##= friction force ##Fg_x## = horizontal gravitational component ##Fg_y## = vertical gravitational component Homework Equations ##F_N=mg~cosθ##...

Two small blocks, each of mass m, are connected by a string of constant length 4h and negligible mass. Block A is placed on a very rough tabletop as shown below, and block B hangs over the edge of the table. The tabletop is a distance 2h above the floor. Block A is then released from rest at a...

Homework Statement A 10 g bullet is fired at 200 m/s into a 1 kg block after which they slide together 2 m on a horizontal surface. Determine the coefficient of kinetic friction between the block and surface. Homework Equations ##M_AV_{Ai} + M_BV_{Bi} = 0## ##WNC = ΔE## The Attempt at a...

Homework Statement A woman holds a book by placing it between her hands such that she presses at right angles to the front and back covers. The book has a mass of m = 0.75kg and the coefficient of static friction between her hand and the book is μs = 0.59. What is the minimum force she must...

Does coefficient of friction change in regard to clamp force applied to parts? If you imagine a bench vice, clamping a plate with a weight attached. Can the clamp force required be calculated to hold a specific weight? I'm asking because I have an excavator mounted hammer EMV outside. It...

Homework Statement Box Mass = 64.7 kg T1 = 22.5° T2 = 54.1° F = 2327.9 N μdynamic = 0.19 μstatic = 0.37 What is the force of friction acting on the box? Homework Equations FF= mu x FN The Attempt at a Solution 64.7 x 9.81 = 634.707 0.19 x 634.707 = 120.69 Computer is telling...

I understand the whole explanation about why static friction does no work-- I'm just confused about one of the consequences of that. Consider the picture above. The ring is being pulled down the incline with a force of mg*sin(θ). If you analyze the system about the axis at the center of mass of...

Homework Statement Solve the free diagram of two stacked boxes on a frictionless table accelerated by a force. Homework Equations [/B] None The Attempt at a Solution I have box 2 stacked on box 1. Box 1 is on a frictionless table and accelerated by a force. However, there is friction...

I was working on a centripetal question where it said that on glare ice, any car needs to travel 60 km/h to successfully make it through the banked highway, and in good road conditions, a car travels at 90 km/k, I had to calculate the coefficient of static friction. When drawing my FBD, I made...

Homework Statement A boy pulls a sled (mass m=59.2 kg) along the ground using a force of magnitude F = 586 N inclined at an angle of θ=37.3° to the horizontal. There is friction between the sled and the ground with a coefficient of µk = 0.205. If the sled starts at rest, how much kinetic energy...

Homework Statement How does an applied force and a frictional force compare when moving at constant velocity? Homework EquationsThe Attempt at a Solution

Suppose I am trying to push a heavy block on ground and I haven't applied a force stronger than the maximum static friction. The force of friction acts on the block and its equal and opposite force acts on the ground. Does the reaction force of friction(acting horizontally on the ground)...

A 10.0 kg box rest on a horizontal board. One end of the board is slowly raised to 12.8° with the floor, the box slides at a constant velocity. (Use this information to find the kinetic coefficient). Find the magnitude and direction of the acceleration of the box when the board is raised to an...

Homework Statement 13.49 The flatbed railway car travels at the constant speed of 80 km/h around a curve of radius 55m and the bank angle 15deg. Determine the smallest static coefficient of friction between the crate and the car that would prevent the crate of mass M from sliding. Homework...

Homework Statement Consider a rope of mass M and length L, resting on a horizontal table, as shown in the figure. The coefficient of kinetic friction between the table and the rope is μk. Let's consider the work that's done by friction as we slide the rope off the table. a.) Consider a small...

Homework Statement Ginny has a plan. She is going to ride her sled while her dog Foo pulls her, and she holds on to his leash. However, Ginny hasn’t taken physics, so there may be a problem: she may slide right off the sled when Foo starts pulling. The sled has mass m, and Ginny has mass M...

On a frictionless road and tires, I know the rider wouldn't be able to change the combined center of gravity of the system by moving his weight around. If he pushes the bike to lean to the right, he would go to the left by the amount that would keep the combined cog the same. But a bike with...

So this is the problem: A 250-kg crate is on a rough ramp, inclined at 30° above the horizontal. The coefficient of kinetic friction between the crate and ramp is 0.22. A horizontal force of 5000 N is applied to the crate, pushing it up the ramp. What is the acceleration of the crate? Relevant...

[note from mentor: this was originally posted in a non-homework forum, so it lacks the homework template.] Hi guys, I need your help with the last part of following problem please. A soccer player with 70kg mass slides for 0.75 seconds on the grass to stop a soccer ball. 1) Acceleration...

Can anyone help with the following question, please? 1. A 60,000kg train is being pulled up a 1 percent grade (it rises 1m for each horizontal 100m). The friction force opposing the motion of the train is 4,000N. Initial speed of the train is 12 m/s. Through what horizontal distance will the...

Lets say I have a massive rod laying on a table with little froction, screwed into the table on one side to become our pivot point, and I lay next to it with my feet pointing towards the rod. First scenario: I position myself very close to the pivot point and push, the rod rotates and I move...

Typically how do the two frictions, namely 1. at the axle of a car wheel vs 2. friction experienced by tyre at the road surface compare with each other? are they some what equal ?.. I am interested in approximate ratio of the two values . Thx.

Homework Statement In a classic carnival ride, patrons stand against the wall in a cylindrically shaped room. Once the room gets spinning fast enough, the floor drops from the bottom of the room! Friction between the walls of the room and the people on the ride make them the “stick” to the wall...

Let's consider a setup consisting of a table with friction, and a block on top of it. Suppose we drag the block across the table with a constant speed. The applied force ##f_{app}## acting through a distance ##d## does a work ##f_{app}d##. The frictional force ##\mu N## is equal to ##f_{app}##...

Homework Statement There is a mass m1 on an incline (angle α), connected to a pulley with a string, and on the other side of the pulley, after another string, there is a mass m2. See picture if it's unclear, I'm not sure how to express the problem. Anyway the plane has a friction coefficient...