Kinetic friction Definition and 509 Threads

Homework Statement A bullet collides and embeds itself into a block hanging from a rope. The block and embedded bullet swing out to an angle of 10 degrees. If the bullet plows 2 cm into the block before stopping, what is the coefficient of kinetic friction between the block and the bullet...

1. Homework Statement [/b] A box weighing 100N is at rest on a horizontal surface. The coefficient of static friction between the box and the surface is 0.5, and the coefficient of kinetic friction is 0.25. If the crate is pushed with a force of 20N parallel to the floor, which of the following...

Homework Statement A sled is pulled with a horizontal force of 15 N along a level trail, and the acceleration is found to be 0.38 m/s2. An extra mass m = 4.2 kg is placed on the sled. If the same force is just barely able to keep the sled moving, what is the coefficient of kinetic friction...

Homework Statement A block of mass " lying on a ramp tilted at an angle  with the horizontal is connected to another block of mass # by a light string passing over a frictionless pulley as shown. If the block slides up the ramp with a constant velocity ), what is the...

An object of mass M is pulled along a rough floor for some time. An additional mass m is then placed on M and is pulled along the same floor as shown. (The picture is just a square with mass M and a small square right on top of it with mass m) What effect does the addition of mass m have...

A slide loving pig slides down a 35 degree slide in twice the time it would taken to slide down a frictionless 35 degree slide. What is the coefficient of kinetic friction between the pig and slide? So with the frictionless slide I found ax=8.03m/s^2 but without velocity or the length of...

Homework Statement This was a lab. We attached a weight to a pulley and connected it to a wooden block. the wooden block was placed on a wooden board on a table. we dropped the weight and calculated the time it to the block to travel a certain distance.We have the variables T=1.28 s Mass of...

A 3.40 kg block is pushed along the ceiling with a constant applied force of 85.0 N that acts at an angle of 55.0° with the horizontal, as in the figure below. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between block and ceiling...

A 3.40 kg block is pushed along the ceiling with a constant applied force of 85.0 N that acts at an angle of 55.0° with the horizontal, as in the figure below. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between block and ceiling...

A 3.40 kg block is pushed along the ceiling with a constant applied force of 85.0 N that acts at an angle of 55.0° with the horizontal, as in the figure below. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between block and ceiling. Ugghhh so...

Heres the problem, A 1,440-N crate is being pushed across a level floor at a constant speed by a force of 270 N at an angle of 20.0° below the horizontal (a) What is the coefficient of kinetic friction between the crate and the floor? I know how to do this. The answer is .165 Heres...

Homework Statement A child goes down a playground slide with an acceleration of 1.26 m/s^2. Find the coefficient of the kinetic friction between the child and the slide if the slide is inclined at an angle of 33 degrees below horizontal. Homework Equations F=MA Kinetic Friction =...

Homework Statement A crate is being pushed up a hill with friction. Given: m1 = 131 kg, θ = 23°, \mus = 0.15, and \muk = 0.08. If the crate isn't being pushed anymore, what will be the magnitude of the acceleration of the crate sliding downhill? What force must be exerted to move the crate...

Homework Statement (there's a diagram that shows a crate on a plane inclined 19.29° above the horizontal) Find the coefficient of kinetic friction. θ = 19.29° mcrate = .205 kg Homework Equations Ff = FN*μk Fg = mg FN = cosθ*mg The Attempt at a Solution I drew out a free-body diagram for...

I'm modeling a moving cart, and I'm trying to determine if the coefficient of kinetic friction changes as a function of speed. Does anyone know of any literature where this is discussed, or if this happens? I would've thought friction solely depends on the types of materials used.

Homework Statement A heavy chain with a mass per unit length ρ is pulled by the constant force F along a horizontal surface consisting of a smooth section and a rough section.The chain is initially at rest on the rough surface with x=0 .If the coefficient of kinetic friction between the...

pHomework Statement A 5.03 box sits at rest at the bottom of a ramp that is 8.76 long and that is inclined at 30.0 above the horizontal. The coefficient of kinetic friction is 0.40, and the coefficient of static friction is 0.50. What constant force , applied parallel to the surface of the...

Kinetic Friction Problem Needs Help! Homework Statement A truck is traveling at constant acceleration. A box of mass 80kg rests in the bed of the truck. The Kinetic Friction between the bed and the box is 0.5. After traveling for 3 seconds the box falls off the back of the truck, what is...

Homework Statement A train has a mass of 5 million kilograms and is traveling south at 22 m/s. If the train driver has to initiate a panic stop, how far will the train go before it comes to a halt. Use 0.08 as the coefficient of kinetic friction. m=5*106 kg v=-22 m/s μ-kinetic...

Homework Statement A skier weighing 90kg starts from rest down a hill inclined at 17 degree. He skis down the hill and then coast for 70 m along level snow until he stops. Find the coefficient of kinetic friction between the skis and the snow. What velocity does the skier have at the bottom...

Homework Statement An object of mass m1=50kg, connected to another object of mass m2=20kg by a cable,is driven up an inclineof 30° by a force F , acting on m1 and parallel to the incline. Assuming a coefficient of kinetic of 0.4 between the two objects and the icline: 1-what should be the...

Homework Statement When the mass M is at the position shown, it has a speed v0 = 2.17 m/s and is sliding down the inclined part of a slide. The mass reaches the bottom of the incline and then travels a distance S2 = 2.45 m along the horizontal part of the slide before stopping. The distance S1...

Hello everyone, i have the following two part prompt and I am having a difficult time with the second part. Here is first part of the prompt, A block of mass 0.528 kg slides with uniform velocity of 4.15 m/s on a horizontal frictionless surface. At some point, it strikes a horizontal spring...

Homework Statement A 10.0kg box is accelerated from rest to 4.00 m/s in 1.00s. The force of kinetic friction on the box is 5.00N. A) What is the size of the applied force? B)What is the coefficient of sliding friction? Homework Equations The five kinematic equations? μ = Ff/Fn Fn=...

Hypothetically, if I had a sphere and a block (of the same mass and material (hence the same coefficients of static friction for both interfaces) both stationary on a surface, they would require the same force to initiate motion? Once moving, a coefficient of sliding friction is employed in...

Homework Statement A crate of mass 10.0 kg is pulled up a rough incline with an initial speed of 1.5 m/s. The pulling force is 100 N parallel to the incline which makes an angle of 20.0° with the horizontal. The coefficient of kinetic friction is .4 and the cart is pulled 5.00 m. e) What is...

This isn't part of a homework question or anything, i was just curious If an object is at rest, static friction is at work, so for an object to move, on a flat surface, force applied must be greater than the static friction force yes? But this is not true for kinetic friction, where an...

Homework Statement A potter's wheel having a radius 0.49 m and a moment of inertia of 10.6 kg · m2 is rotating freely at 52 rev/min. The potter can stop the wheel in 5.5 s by pressing a wet rag against the rim and exerting a radially inward force of 68 N. Find the effective coefficient of...

Homework Statement A block of mass m is initially held in place on the left side of a track at a distance h above the bottom of the track. The track is completely frictionless, with the exception of a rough horizontal section of track of length h which has a coefficient of kinetic friction μ...

Homework Statement A system comprised blocks, a light frictionless pulley, and connecting ropes is shown in the figure. The 9.0-kg block is on a perfectly smooth horizontal table. The surfaces of the 12-kg block are rough, with muk (kinetic frict constant) = 0.30 between the block and the...

Homework Statement Which of the following statements about friction is correct? I. Kinetic friction always decreases the mechanical energy of a system. II. The static friction force cannot change the mechanical energy of a system. III. The force of friction always points in the direction...

Homework Statement A box is sliding down an incline tilted at a 13.0° angle above horizontal. The box is initially sliding down the incline at a speed of 1.40 m/s. The coefficient of kinetic friction between the box and the incline is 0.370. How far does the box slide down the incline...

Homework Statement While sliding, the only force acting on the block in the horizontal direction is that of friction. From the mass of the block and its acceleration, you can find the frictional force and finally, the coefficient of kinetic friction. Okay, so we are sliding a steel block with...

Homework Statement A block of ice of mass m slides down an incline that makes an angle θ = 40.7° with the horizontal. In trial 1 there is no friction; the block starts at rest and takes time t to reach the bottom of the incline. In trial 2 there is friction, and the the block slides down the...

Homework Statement m = 52kg theta = 10.3deg t = 5.8s d = 3.63 m Homework Equations The Attempt at a Solution Ok so here are my attempts. If they are way off, take it easy on me :). I am not very good at this. Am I missing negatives or am I way off on this? Are my trigs...

Homework Statement 1. Homework Statement A block of mass 0.015kg enters the bottom of a circular, vertical track with a radius R = 0.3m at an initial velocity of 4/ms. If the block loses contact with the track at an angle of 130 degrees, what is Wk, the work done by kinetic friction...

Homework Statement A box slides down a 31 degree ramp with an acceleration of 1.42 m/s squared. determine the coefficient of kinetic friction (mew) between the box and the ramp. Homework Equations F=ma Fnet=ma Fn(µ)=Ff The Attempt at a Solution Many attempts on paper but unable...

Homework Statement A construction worker passes a brick to another worker by pushing it across a wooded floor. the brick has a mas of 2.7kg. The force required making the brick move with acceleration of 0.42m/s2 is 28 N. What is the co-efficient of kinetic friction acting on the brick? The...

Homework Statement A 65.0kg person, running horizontally with a velocity of +4.25 m/s, jumps onto a 12.0-kg sled that is initially at rest. 1) Ignoring the effects of friction during the collision, find the velocity of the sled and the person as they move away. 2) The sled and the person...

Homework Statement A crate is pushed at constant velocity across a rough, horizontal surface by a push force P. The crate has a weight of 73N. Coefficient of kinetic friction between the crate and the floor is 0.41. Vector force P points at an angle of 37 degrees below the horizontal. What...

Homework Statement A toboggan carrying two children with a total mass of 85.0 kg reaches its maximum speed at the bottom of a hill, and then glides to a stop in 21.0 m along a horizontal surface. The coefficient of kinetic friction between the toboggan and the snow surface is 0.110. Calculate...

Homework Statement In the following figure(one box on a table, m1, connected to a string that is on a pulley attached to box m2), m1=10kg and m2=4kg. The coefficient of static friction between m1 and the horizonatl surface is 0.50 while the coefficient of kinetic friction is 0.30. (a) If the...

Homework Statement Im working on some typical "Ramp being pulled up an incline" questions and have trouble understanding something. An example question where it stats a box is being pulled up a ramp like the image below: Image: http://i43.tinypic.com/jb486q.jpg Now, first: In order...

At the bottom of a hill, a snowboarder with a velocity of 16m/s (FWD) skids to a stop after moving a distance of 9.4m. The mass of the board and rider is 71kg, and the magnitude of the force of kinetic friction during the skid is 950N. Determine the coefficient of kinetic friction during...

Homework Statement A 62 kg crate is dragged across a floor by pulling on a rope attached to the crate and inclined 16° above the horizontal. (a) If the coefficient of static friction is 0.57, what minimum force magnitude is required from the rope to start the crate moving? (b) If μk = 0.31...

Homework Statement Julia is delivering newspapers. Suppose she is driving at 15 m/s along a straight road and wants to drop a paper out the window from a height of 1.00m so it slides along the shoulder and comes to rest in the customer's driveway. At what horizontal distance before the...

Homework Statement Suppose the coefficient of kinetic friction between m1 and the plane in the figure is μk=0.20, and that m1=m2=2.2kg. a) As moves down, determine the magnitude of the acceleration of m1 and m2 given θ=28o. b) What smallest value of μk will keep this system from...

NEED CONCEPTUAL HELP ONLY! A package of eggs (mass 60.0 kg) sits on the flatbed of a pickup truck with an open tailgate. The coefficient of static friction between the package and the truck's flatbed is 0.350, and the coefficient of kinetic friction is 0.250. a) The truck accelerates...

Homework Statement When you push a 1.55 kg book resting on a tabletop it takes 2.50 N to start the book sliding. Once it is sliding, however, it takes only 1.50 N to keep the book moving with constant speed. What are the coefficients of static and kinetic friction between the book and the...

Homework Statement When three blocks are released from rest, they accelerate with a magnitude of 0.500 m/s2. Block 1 has mass M, block 2 has 2M, and block 3 has 2M. What is the coefficient of kinetic friction between block 2 and the table? (The blocks are arranged with block 1 hanging from...