Friction Definition and 998 Threads

Homework Statement A 10.0 kg sphere is attached to the incline by a horizontal string. Whats the tension in the string. Homework Equations sum of all horizontal forces = 0 sum of all vertical forces = 0 sum of all torques = 0 The Attempt at a Solution The sum of the horizontal forces[/B] is...

Homework Statement Rub the two books together for a long time, so that the thermometer goes all the way up to the top and all the extra molecules fly off the top book. Keep the books touching, but stop rubbing. The temperature will go down. How can you tell? List two different ways...

Hi, I'm looking at a friction hinge design problem. See the image below for details. Looking through a machinist's handbook (pg. 1495), I get a few equations for fastener preload and wrench torque. T = k * Fi * d, where T is wrench torque, Fi is preload, and d is the nominal bolt diameter, and...

Using an ablative carbon-carbon heat-shield, what thickness would be used up? Or might a ceramic insulator be able to handle it? What would happen if the nose was solid aluminium?How can this be calculated? What information do I need to figure this out?

Homework Statement Hey, guys I'm having trouble solving this problem, I'm not sure what to do first This is the info it gives: A stationary 15 kg object is located on a table near the surface of the earth. The coefficient of static friction between the surfaces is 0.40 and the coefficient of...

How can we calculate the friction between the wheels and the surface in contact? I know that big wheels will have a greater friction, but what is the formula to calculate it?

Hi all, Can anyone please help me out with the direction of friction in a case where there is a smooth spherical body pure rolling on a rough surface? What is the direction of friction? Also, is it possible to have pure rolling without friction? Thanks SD

I have been wondering this for a while. I know that tires using static friction due to reasons that I forget and therefor maintain good traction with asphalt. A few years ago family member said that if there was too much friction on a road then a car wouldn't move, but I argued that the car...

Homework Statement I have solved the problem where one mass m1 is on a horizontal frictional table connected to a mass m2 which is hanging off the table by a string over a pulley (assuming pulley massless), assuming that m2 is greater than m1 there is a net acceleration causing the mass 2 to...

I'm a games programmer who is writing a simple car physics simulation, and I've had a disagreement with the designer about a car's behaviour - specifically, its top speed - in different conditions. Imagine a car accelerating from a standing start to top speed along a perfectly straight, flat...

Homework Statement So far i know that the uncertainty of the force of friction is +/- 0.1 and the uncertainty of the force normal is +/- 0.1 also. Homework Equations Force of friction=(myoo)(force normal) Myoo= force friction / force normal The Attempt at a Solution My data is Force of...

Homework Statement The mass of A is 5kg and the mass of B is 10kg. If the acceleration of A is 2m/s^2 which is smaller than acceleration of B, where A is placed on top of B, then the value of frictional force applied by B on A is: A) 50N. B) 20N. C) 10N. D) None of these Homework Equations...

Homework Statement A 2000 kg plane is landing at an airfield with an initial speed of 50 m/s. The force of friction is 1/4 the weight of the plane. What is the acceleration of the plane? Homework Equations Fnet = ma Fnet = something - ff The Attempt at a Solution 2000a = thing I don't know...

Homework Statement I am trying to craft a hypothesis regarding factors that affect the coefficient of friction. I know that it is determined by the triboforces and asperity interactions at the interface between the materials (among other factors, but right now I'm just going to focus on this)...

Homework Statement A solid ball of mass M and radius R and moment of inertia I is placed onto a table with an initial velocity v_0 to the right and angular momentum w_0 anticlockwise (i.e the ball has backspin). Due to friction, the angular velocity and linear velocity changes as the ball both...

Homework Statement Homework Equations ΣFx=max The Attempt at a Solution I drew a free body diagram for the box and set up the equation to solve for θ, but I'm not sure how to do it without μ

I'm not sure whether I understood rolling friction properly. First, I'll assume that both surface and the body are completely rigid (no deformations of body nor surface will happen, thus vector N won't be dislocated creating an opposite momentum). So, rolling friction (assuming there is friction...

I not understand because why if I have a (constant) force of friction and I apply the curl, I finding that this not is equal to zero, since this force is non conservative.

Homework Statement The carriage and its passengers start at rest at A. At B, the bottom of the ride, the maximum speed of the carriage is 20ms-1. The vertical distance between A and B is 110m. The length of the track between A and B is 510m. The mass of the carriage and the passengers is...

Its for my final project. We are doing a sliding a textbook down an *incline plane* and we are expected to find coefficient of static friction without using Newton guage, and we are also now allowed to use kinematics. I just need some infomration on how to do this, like a formula or something in...

Homework Statement "Before the collision, vehicle #1 was traveling east and vehicle #2 was traveling north. The driver of vehicle #1 states he was traveling 35 mph as he approached the intersection. He continues to state that vehicle #2 ran the stop sign, pulling out in front of him and...

My understanding through most of college has been that friction occurs because of the surface roughness of two materials rubbing together; the smoother you make the surfaces, the less friction you have. Upon further research I can see that is not the entire case. Another problem for me is that...

Suppose that the ball exits the net going straight down at a velocity of just 0.600 m/s. What is the force of friction between the net and the ball, provided that the net contacts the ball throughout a length of 0.381 meters? The mass of the ball is 0.5kg. (The approximate answer is 9.0N) I...

Homework Statement 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 acceleration the car can achieve (in the direction upwards along the hill)? Neglect the rotational...

When a body is in motion , does kinetic and static friction act simultaneously

Homework Statement A man pulls a 15-kg sled containing a 5.0-kg dog along a straight path on a horizontal surface. He exerts a force of 55 N on the sled at an angle of 20.° above the horizontal, as shown in the figure above. The coefficient of friction between the sled and the surface is 0.22...

Hi As described in my previous post I am looking to make a foldable mechanism of an arm hinge. I have changed my design into the one shown in attached image. I plan to use spring split or coil pin to constrain radial movement in the hinge (yellow and red). Adding a bolt through the hinge...

Homework Statement A roller coaster is going down on a track (see image below, the track itself is highlighted in red) without initial velocity. What is the coefficient of friction between the roller coaster and the track? height at which the cart starts (h) = 12m weight of the car (m) = 620kg...

Homework Statement If you have 2 boxes over each other in a car that is slowing down . The mass of each one of them is 10kg and Us = 0.4 for all surfaces. What is the maximum deceleration that doesn't make the boxes fall? And will it make different if you change the masses of the objects? 3...

Does rolling friction depend on the surface area? In other words, the size of the object placed? If I had a block and sphere of the same mass. Without static and kinetic friction coming into play. Which would experience greater rolling friction if they were on the same incline and of the same...

Homework Statement You are called to the site of a collision between a small car and a half ton truck on a lonely country road. You are given the following information: a) On clean dry pavement at a temperature of 20 C, the coefficient of kinetic friction is 0.600 on locked wheels. b)...

Homework Statement A 500-N person stands 2.5 m from a wall against which a horizontal beam is attached. The beam is 6 m long and weighs 200 N (see diagram below). A cable attached to the free end of the beam makes an angle of 45 degrees to the horizontal and is attached to the wall. a) draw a...

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Homework Statement Let's say I am pushing a couch with 30 N, the velocity is constant, therefore, the friction is also 30 N but in the opposite direction. But if a push it with 50 N then the friction force is going to change to 50 N as long as it is not accelerating. So how am I supposed to used...

Homework Statement Brick is sliding off a roof, starts at the peak of the roof (7.0 m above ground), slides down roof with kinetic friction value of 0.28, very edge of roof is 4.0 m above ground. Where does the brick land on the ground? Please see image - http://imgur.com/wNdtlWD Homework...

Homework Statement A block of mass "m" is pulled across a rough table by a string at an angle "θ" above the horizontal at a constant velocity. What is an equation for the magnitude of the kinetic friction force, fk? The answer that I was given was μk(mg-T*cos(θ)) Homework Equations Fk=Fn*uk...

Homework Statement I'm having trouble finding the coefficient of kinetic friction for a lab using spring scales. Mass=.411kg Normal Force=4.0278 Average Pull Force=.46N Frictional Force= -.46NHomework Equations μ k = Fk / N. The Attempt at a Solution μ k = -.46N/4.0278 μ k = -.1142

if I had a motor with a pendulum and a magnet at the end of it, and attached to this motor was a frame holding a another magnet that is close enough to the pendulum to exert force on it when it is horizontally positioned would that force make friction with the inside of the motor creating thrust...

please explain the phenomenon of friction acting on a car moving in a circular track.also explain how is this friction static and how is this friction different from the friction acting on a car moving on a straight road.

please explain why? Take 2 cases,and explain how is the direction of friction different in these 2 cases. CASE 1:uniform circular motion CASE 2:non uniform circular motion my thought was,friction opposes relative motion,so it must be tangential to the particle at each and every point. i very...

Another classic case of "I understand it in reality, but on paper it just makes no sense and I'm confused". There is an object sliding north on a surface where the normal is 10N. The co-efficient for kinetic friction for the surface is 0.5. Simple math will tell me that the force of friction...

Homework Statement 1) According to an object's distance vs. force (parallel) graph, what is the work done in this process as the object moves from 2 m to 8 m? 2) a book is pushed up an 8 degree inclined plane with an initial speed of 11 m/s. If the coefficient of kinetic friction between the...

Homework Statement A box was dragged downward from the state of rest through an inclination 10.0 m at an angle of 25 degree. The speed when the box arrived at the base is 3 m/s. a) what is the coefficient force between the box and the surface? b) how many work is done to move the box downward...

Various types of friction operate in all relative motion of materials. Boundary layers in the flow over on wings, Fatigue in metals subject the oscillatory bending. Friction between a car tire and the road. these are just some examples of the holistic impact on operations here on Earth. Does...

Homework Statement A man is exerting a force of 200 N on a refrigerator and pushing the fridge across a rough floor at a constant velocity to the right. How much friction force acts on the refrigerator ? Give a number and appropriate units. Homework Equations none The Attempt at a Solution I...

Hi everyone This is my first post on the forum. I work in engineering and use this forum to answer questions from time to time. I am looking for confirmation of my understanding of static rotation torque (not something I deal with in day to day work). Imagine 2 identical discs or washers that...

Homework Statement 2 trucks, one with twice as much mass than the other, are at rest on separate tracks. A man pushes each truck for 5 seconds. If you ignore friction and assume equal force is exerted on both trucks - which truck will have the most kinetic energy afterwards? Homework Equations...

Homework Statement #11 Homework Equations a = Fnet / m The Attempt at a Solution Fw= 80 * 9.8 = 784 (.30)(80.0)(9.8) = 235.2

Homework Statement A gate is supported by two rings at A and B that fit over a vertical rod as shown. If the coefficient of friction between the rings and the rod is 0.2, find the maximum distance between the rings for which the gate is in equilibrium. The reaction at the upper ring is directed...

Homework Statement The question on this paper is as follows: 'Why is it vital that there is a friction force that opposes motion when two surfaces try to slide across one another?'. My response was: 'If there was no friction, something will keep on going in one direction if no other forces act...