Coefficient of friction Definition and 411 Threads

Homework Statement We have a block of wood that has a weight of 95.5g lying on another flat piece of wood. The block of wood has a string attached to a tray that hangs over a pulley. Wehad to add weight to the block adn then to the tray to see how much weight in the tray would break the...

Homework Statement A block of wood is sitting on an inclined plane. One end of the plane is rised until the wood block slides down. The wood block slides down when the plane has an angle of 17.157 degrees . What is the coefficient of friction? Homework Equations F/R The Attempt...

Homework Statement A book has a mass of 400 g. When you slided the book against the floor with 5 N, it accelerated at the rate of -1.5 m/s2. What would the coefficient of friction between the book and the floor be? Homework Equations F = ma W = mg FN = - mg The Attempt at a...

Homework Statement A mop is being used to clean a floor. The coefficient of friction between the mop and floor is 0.3. Find the angle between the handle and the horizontal when the mop head is moving at constant velocity. Homework Equations The coefficient of friction = Friction/ Normal...

Homework Statement A 3 kg block slides down a 30 degree inclined plane with constant acceleration of 0.5 m/s2. The block starts from rest at the top. The length of the incline is 2 m. What is the coefficient of friction between the plane and the block? Homework Equations Ff=uFn...

Homework Statement Jeff Gordon (a race-car driver) discovers that he can accelerate at 4.0m/s2 without spinning his tires, but if he tries to accelerate more rapidly he always "burns rubber." Find the coefficient of friction between his tires and the road. Assume the force from the engine is...

I know the steel-steel COF is about 0.8. Are the tribological properties of different steels, eg austenitic and 9%Cr, sufficiently different that this difference should be taken into account in the design of a component that will slide over two different steels, or sufficiently similar that the...

why the coefficient of friction of screw jack of two pulley is negative in lowering state?

This is my first year teaching High School Physics and I'm finding there are a lot of questions I should have asked 25 years ago when I was in college. 1. Does anybody know what the coefficient of friction is based on? Usually these things are based on something like getting units to cancel...

Homework Statement Please help this is due tomorrow. I was made to do an experiment and here it is. I had to designate a fixed starting point, drive at 10 mph until that point, put the car into neutral and see how far it drifted until it stopped. Then I was instructed to go the opposite way...

Homework Statement You pull on a crate with a force of 50N at an angle of 25 degrees. The box doesn't move.? What is the coefficient of friction and what is the frictional force? I understand the forces are balanced, but are they balanced in the x and y direction. I've done the problem ...

Homework Statement For a shoe, does its size or mass affect its coefficient of friction? Explain their effects. Homework Equations Ff=muFn The Attempt at a Solution I'm thinking the mass does (because you need the mass to find the normal force) and the size doesn't because it isn't...

Homework Statement If a car's wheels are locked during emergency braking, the car slides along the road. The record for the longest skid marks on a road was reportedly set in 1960. the marks were 290m long. assuming that \mu = 0.6, how fast was the car going when the wheels became locked...

Homework Statement My task is to design a lab in which i can solve for the coefficient of friction for a razor scooter( the little medal kids one). I planned on varying velocities and distance to show that the coefficient remained constant. Does anyone see any improvements that could me...

Homework Statement if i am missing something that prevents you from answering and let me know ill try and add it A block pulls another block across a wooden surface via a pulley at a constant speed. the surface is horizontal the mass of the block on the horizontal surface is unknown...

Homework Statement A block accelerates at 3.7 m/s^2 down a plane at an angle of 26 degrees. Find the coefficient of kinetic friction between the block and the inclined plane. The acceleration of gravity is 9.81 m/s^2.* Homework Equations \SigmaF = ma F_{}k = \mu_{}k * F_{}n The...

Homework Statement the coefficient of starting friction for wood on wood is 0.55. What is the force of friction of a wood block of mass 3.5 kg being pulled on a wood floor? Homework Equations i think i use the formula F=mMA where F is the force needed to move a solid from rest...

Homework Statement A horizontal force of 200 n is required to cause a 15 kg block to slide up a 20degree incline with acceleration of 25 cm/s^2. Find the friction force on the block and the coefficient of friction. ANSWERS: Friction force = 134N Coefficient of Friction = 0.65 Homework...

Homework Statement Find the coefficient of kinetic friction between a 4.3- block and the horizontal surface on which it rests if an 89 spring must be stretched by 2.3 to pull the block wi`th constant speed. Assume the spring pulls in a direction 15 above the horizontal. Homework...

Homework Statement A car is traveling at 66.9 mi/h on a horizontal highway. The acceleration of gravity is 9.8 m/s2 . If the coefficient of friction between road and tires on a rainy day is 0.13, what is the minimum distance in which the car will stop? (1 mi = 1.609) Answer in units of m...

Homework Statement A banked circular highway curve is designed for traffic moving at 56 km/h. The radius of the curve is 203 m. Traffic is moving along the highway at 51 km/h on a rainy day. What is the minimum coefficient of friction between tires and road that will allow cars to negotiate...

Homework Statement A race-car driver discovers that he can accelerate at 4.0 m/s2 without spinning his tires, but if he tries to accelerate more rapidly, he always "burns rubber." What is the coefficient of friction between his tires and the road? Answer behind the book: Homework...

I need help with my homework. http://img36.imageshack.us/img36/8717/friction.png Uploaded with ImageShack.us I don't how to figure this out because you only get velocity :/

Homework Statement A skier coasts down a 3.5 degree slope at a constant speed. Find the coefficient of kinetic friction between the skis and the snow covering the slope. Homework Equations coefficient of friction x Normal force = force friction therefore: coefficeint of friction =...

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 so they do not...

Hello, I am looking for static and dynamic coefficients of friction for bronze on stainless steel (dry condition). Closest thing I could find was http://www.engineershandbook.com/Tables/frictioncoefficients.htm" where it only has steel on bronze under greasy condition. Can anyone help me...

Did my teacher incorrectly write this problem? I looked at it for a good 20 minutes straight before posting this on here.. It's so easy but I think there is something wrong. 1.) The Wheels of a 1.450 x 10^3 Kg car car are locked so that it can only slide on wet concrete at a constant speed of...

Homework Statement A car is traveling at 56.0 km/h on a flat highway. If the coefficient of friction between road and tires on a rainy day is 0.100, what is the minimum distance in which the car will stop? Homework Equations μ=-a/g v2=vo2 + 2 a x The Attempt at a Solution 56.0...

What is the minimum work needed to push a 1000 kg car up 45.0 meters up a 12.5 \circ degree incline? a. Ignore Friction b. Assume the effective coefficient of friction is 0.30. Work: W = (F*d)cos\theta Coefficient of friction: W = \muN(d) What I did: W = (m*g)(d)cos\theta...

Here's my givens... i need to find the coefficient of friction on the material. No load torque on motor - 3.19 Nm Loaded torque on motor - 3.49 Nm Surface area in contact with motor shaft - .1885" Mass of loaded material on shaft - 17.16 lbs = 76.33 N Rads/sec - 31.42Looking to find the...

Homework Statement A waterslide ride consists of a straight guided ramp, at an angle theta (to the horizontal plane), with a transition to a short horizontal section at the bottom of the slide (1m long), just above the surface of a splace pool of length L. Patrons queue on a platform of...

You pull your 20 kg little brother horizontally across a beack on a .7 kg innertube at 65 N to get the tube moving. What is the coefficient of static friction between the sand and the tube? You keep pulling at 60 N with the innertube at a constant velocity. What is the coefficient of kinetic...

Homework Statement A ring on a rod of weight 8 N. A 7 N force at an angle of 45 degrees to the rod is acting away from the ring. The system is in limiting equilibrium. Find the coefficent of friction between the rod and the ring. Homework Equations Quite obvious. The Attempt at a...

Homework Statement A book has a mass of 400 g. When you slide the book against the floor with 5 N, it accelerated at the rate of -1.5 m/s^2. What would the coefficient of friction between the book and the floor be? Homework Equations Ff = μFN The Attempt at a Solution I am trying to...

EDIT: Never mind, I figured it out, please ignore this or mods delete it.

Homework Statement A bullet with a mass of 7.00 g is fired horizontally with a speed of 420 m/s, into a wooden block with mass of 0.820 kg, initially at rest on a level surface. The bullet passes through the block and emerges with its speed reduced to 130 m/s. The block slides a distance of...

Homework Statement What is the coefficient of friction between the road and the wheels of a 1400kg truck accelerating at 2 m/s/s if the force applied by the engine to the wheels is 4000N. Homework Equations Fn = m * g Ff = mu * Fn The Attempt at a Solution I do not know how to...

Homework Statement A skier traveling 12.6 m/s reaches the foot of a steady upward 15.2° incline and glides 12.0 m up along this slope before coming to rest. What was the average coefficient of friction? Homework Equations The Attempt at a Solution D = 12m Velocity initial =...

Homework Statement A horizontal force of 2 N is just sufficient to prevent a block of mass 1 kg from sliding down a rough plane inclined at arcsin \frac{7}{25} to the horizontal. Find the coefficient of friction between the block and the plane and the acceleration with which the block will move...

Homework Statement A small 10kg cardboard box is thrown across a level floor. It slides a distance of 6.0m, stopping in 2.2s. Determine the coefficient of friction between the box and the floor. Homework Equations \[\Delta d={{v}_{0}}t+\frac{1}{2}a{{t}^{2}}\] \[{{F}_{net}}=ma\] The...

Homework Statement A box weighing 3.0 kN is placed in the bed of a pick-up truck. The pick-up accelerates uniformly from rest to 40 km/h in a distance of 40 m. In that time the box slides 1.0 m back toward the end of the bed. Find the coefficient of friction between the bed and the box...

Homework Statement A mass of 50 kg is kept in uniform motion along a horizontal surface by a horizontal force of 4.08x10^6 dynes. What is the coefficient of friction between surface and the mass? Homework Equations (I searched previous answered questions and found this) Ff= u * mg...

Homework Statement The coefficients of friction between the load and the flat-bed trailer shown are \mus = 0.40 and \muk = 0.30. Knowing that the speed of the rig is 45 mi/h, determine the shortest distance in which the rig can be brough to a stop if the load is not to shift. The drawing...

Homework Statement Hello, How do i find coefficient of friction knowing only mass, velocity and incline for a inclined plane? Homework Equations The Attempt at a Solution

Coefficient of Friction of object sliding down ramp.. need help! Homework Statement An 10.0kg object slides down an inclined plane that is 10.0m in length. THe height of the incline is 6.0m and the speed of the object at the bottom is 9.0 m/s. What is the coefficient of friction of this...

Homework Statement A hockey puck leaves a player's stick with a speed of 9.90 m/s and slides 35.0 m before coming to rest. Homework Equations Find the coefficient of friction between the puck and the ice. The Attempt at a Solution I don't even know how to approach this problem

Homework Statement Why do brakes and clutches need high coefficient of friction? Homework Equations Pls give applications where engineers need to have materials having low values for the coefficient of friction The Attempt at a Solution

Hi all *Pls can somebody tell me why clutches and brakes need high coefficient of friction *also i need applications where engineers need to have materials having low values for the coefficient of friction Thanks

Homework Statement A car moving at 5 m/s tries to round a flat corner that has a radius of curvature of 8 m. How large must the coefficient of friction be between the wheels and the roadway if the car is not to skid? Homework Equations mv^2/r i don't know anything else. Fc=Fn(mk)...

I have some very small spherical particles with diameter of 1 mm and i would like to know coefficient of friction between them. Can anyone suggest an experiment/device that would help me? In order to get friction between a plate and particle i can use tilt test and measure the angle at which...