Frictional force Definition and 255 Threads

Does the static friction get converted into kinetic friction while moving

A question from a classical mechanics past paper described a particle of mass ##m## that had a pair of horizontal identical springs of spring constant ##k## attached on either side and that the mass is free to move horizontally. The mass is also placed on a table that gives rise to an...

Ok so for a project of mine I need to calc. the force required to steer an articulated heavy on road vehicle and to overcome friction (so I need to calc frictional forces too). I understand I need to draw FBDs but it has been a while since i have done that and I have never worked with an...

Homework Statement A mass-spring system consisting of a mass of 2.9 kg attached to a spring is subject to a frictional force which is both proportional and opposite to the velocity. The mass is displaced from rest and oscillates back and forth with an ever decreasing amplitude. It is found that...

Homework Statement In the picture Homework Equations Torque = I * Alpha Alpha = a / r Fnet = m*a The Attempt at a Solution I provided my work in the pictures. I figured out that the frictional force in system B is greater than in system A. I am not sure how to compare this with the...

Homework Statement A person is dragging a packing crate of mass 100 kg across a rough floor where the coefficient of kinetic friction is 0.400. He exerts a force F just sufficient to keep the crate moving at a constant velocity. At what angle above the horizontal should his pulling force F be...

Homework Statement A 1453kg car rounds a curve of 122-m radius at a speed of 48 km/h. How large must the force of friction between tires and pavement to prevent the car from skidding? Homework Equations F=(coeficient)mg Net force=Ff+Fcen*cos (-) +mgsin(-) tan(-)=(v)^2 / grThe Attempt at a...

Is there an example in which friction acts in direction of motion. Any special case.

Homework Statement Okay so there is a wall that has a mass of 150 kg and I am pushing it but the wall does not move. The coefficient of friction is 2 and I am trying to find the frictional force using the frictional force formula. Although, I need the normal force in which I am using to push...

Homework Statement I'm trying to create a simple excel simulation for runaway electrons using a given energy-loss per unit distance equation (Bethe formula). I'm stepping through time (pico-seconds) and giving the the electric field some initial value at a distance of 1mm and from there...

Homework Statement A[/B] crate sits in the back of a truck that is accelerating to the right. The crate does not move relative to the bed of the truck. Draw the free body diagram and sum the forces for the crate only.Homework Equations F⃗ net=ΣF⃗ =ma⃗ fs≤μsN [/B]The Attempt at a Solution...

1. A magazine reports that a new type of plastic ski is even more water repellent and that, on a gentle 203-m slope in the Alps, a skier reduced his time from 61 to 42 s with the new skis. Assuming a 3.0 degree slope, compute the coefficient of kinetic friction for each case. I am having...

1. Homework Statement The system is in equilibrium. All the surfaces in the image are rough. The direction of friction on B due to A is : (a) is upward (b) is downward (c) is zero (d) depends on the masses of A and B. ANS : (a) Homework Equations MAg = 2μN (Friction due to wall and due to B)...

Homework Statement The force applied to a cart is 10.5 N. The cart now moves toward the right at an acceleration also toward the right of 1.75m/s2. What are the magnitude and direction of the frictional force? The attempt at a solution I found that my mass is 6kg. I have F, m, and a, but I am...

Homework Statement An applied force of 30N acts on a 8kg box at an angle of 40 degrees above the horizontal. What is the acceleration of the block if =0.1 and μk = 0.05? What is the acceleration of the block without any friction? Homework Equations Equation 1 F k = μ k F N...

Actually I've been thinking about friction lately and it got me a bit confused I was always taught that friction is in the direction that opposes motion, however whenever I learned about static friction I sort of just went with it. It made sense, but I never actually thought about vectors (which...

Hi Guys, I am trying to understand that how does the frictional force on a car moving in a circle is directed towards the centre? I do understand that kinetic friction acts tangentially to the motion and opposite to the velocity vector but why does static friction act towards...

The full problem is: "A 2.0kg box slides down at constant velocity between two identical walls. What is the frictional force exerted on the box by one of the walls?" The answer I got was zero because I equated Normal force (of the wall on the box) at zero. Am I wrong? ): Does the weight of the...

The classical approximated formula describing frictional force is f = N\mu, directed oppositely to the motion direction. What about that kind of friction that arises when N is 0? How can I account of that? For example, suppose I let a cylinder fall inside a pipe nearly the same size, so that...

Frictional force opposes relative motion and not just motion. Can you please give an example to further explain this statement? :confused:

these are technically not homework, i just need more help for my test tomorrow! I HAVE NO IDEA HOW TO DO THIS! can someone walk me through these and show me the steps! thank you :):confused: 1.A sled is being pulled to the right with a force of 28 N. A frictional force is working opposite...

Homework Statement A motor car with a power output of 2500W is moving against a constant frictional resistance of 180N. What distance does it travel in 1 minute on a horizontal road? P = 2500W FF = 180N t = 60s s = ? Homework Equations P = W/t W = Fs Fnet = FA - FF The Attempt...

When a body is held or rests in equilibrium in contact with a surface (e.g. a slope, the edge of a block etc.) how do we work out which direction the friction acts in? I'm used to the friction acting parallel to the surface i.e. slope but in one question I have, of a beam resting on the edge of...

Homework Statement Using the relation ## tan \theta = \mu_k ## what angle should the rope make with the horizontal in order to minimize the work done per unit distance traveled along the ground. Homework Equations ## W = Fdcos\phi ## The Attempt at a Solution I found...

Recently, I have done an experiment of frictional on rolling object. In the experiment, I have done 7 trials with different axle radii, similar to that of a yoyo on a horizontal table. the experimental was set as this As derived by the lab manual i received, frictional force can be...

Will you please explain where actually the force due to friction acts while a man is walking forward. I am really confused with a lot of confusing things in the internet. I am unable to give a fixed answer to my students. I saw somewhere that friction acts in forward direction, please...

Homework Statement A car (m = 1680 kg) is parked on a road that rises 17° above the horizontal. What are the magnitudes of (a) the normal force and (b) the static frictional force that the ground exerts on the tires? Homework Equations FsMAX = Mu*FN or in this case: FsMAX =...

Why isn't the force of friction F= (frictional constant)(force of gravity)? Since F = mg(coefficiant) and g is negative denoting the direction of the vector, gravitational force.

Look at line a,assume it is not sliding down.Line b is sliding down,which means the frictional force of floor is smaller than F. Line is of mass 1kg.Length is 2m, so C.M is in 1m How do you find the force F interms of L,Lh, Lv,m each case? L is the length of line. Lh is the horizontal...

Homework Statement A 2,200-kg car is moving down a road with a slope (grade) of 14% at a constant speed of 11 m/s. Homework Equations The equation that I'm using is ƩF=ma and friction=μN The Attempt at a Solution the mass is 2200kg the acceleration is zero because of the constant...

Homework Statement Find the frictional force (magnitude and direction) on the crate if the crate is sliding up the ramp. Frictional force= ? μk = 0.30 μs = 0.74 mass=10.0 kg angle of incline 30° to the horizontal Homework Equations fk=uk * N The Attempt at a Solution I...

when a body is slided or move in a horizontal floor, the Frictional force is directly proportional to the Normal force acting on the body. Is there is any proof (emperically or Theoretically)

Homework Statement does surface area to affect the values of coefficient µk? Homework Equations frictional force =µk * normal force The Attempt at a Solution I know that if mass is larger then the frictional force is higher( f= ma) but how about the surface area? does it affect...

Hey there, I'm new! :D The weight, which is mass according to the gravity, and this scalar force keeps the object on to the ground, and if a force pushes the object horizontally, then why can't be the mass according to the gravity (weight) be modeled as a frictional force resisting the...

Hello. I am studying material physics. I heard in the class that every adhesion or bonding can occur only with frictional force. Today, I tried to find a proper reference for this statement but I could not. Is there any reference that every adhesion or bonding(esp. Injective...

Hi guys currently submitting a report for a lab experiment we carried out in college. This was to determine the frictional force of a Rotational Velocity Apparatus. I have successfully carried out the relevant calculations and in conclusion to my submitted report, I have to explain the...

[FONT="Arial"]Frictional Force is mathematically defined as: Ff = μ*m*g*cos(θ) , where μ is the coefficient of friction, m is the mass of the object, g is the acceleration due to gravity and θ is the angle of the inclined plane. But in terms of direction, this makes no sense! Suppose...

[b]1. Calculate the frictional force of a crossbar sliding at a constant velocity on two railings. Answer. 1.26 N Given, Crossbar= 256 Ω Distance (separation of railings)= .35 m V (Setup connected to battery)= 12 V B (Magnetic field)= 1.2 T [b]2. Fb=...

Since friction is a "force" and is able to stop a moving object, why doesn't it possesses energy? For example, light, which is an electromagnetic wave, is emitted from a source which have the energy to "do light". Then what is the source of friction? An object cannot just intrinsically...

Homework Statement 2. A block of mass 35 kg is on a flat floor with a static friction coefficient of 0.36 and a kinetic friction coefficient of 0.29. A person attempts to slide the box from rest in a forward direction. Find the maximum frictional force experienced and the acceleration of...

Homework Statement If you push a chair across a carpet at a constant velocity of 0.5 m/s, how does the force you are exerting on that chair compare with the force the force of friction? If you increase the force you are exerting, how does the new frictional force compare with the previous...

[b]1. A 5kg block is held at rest against a vertical wall by a horizontal force of 100 Newtons. 1-What is the frictional force exerted by the wall on the block 2-What is the minimum horizontal force needed to prevent the block from falling if the static coefficient of friction between the wall...

A 2.50 kg block is initially at rest on a horizontal surface. A horizontal force F of magnitude 6.71 N and a vertical force P are then applied to the block. The coefficients of friction for the block and surface are μs = 0.4 and μk = 0.25. Determine the magnitude of the frictional force acting...

Homework Statement I am having trouble understanding the direction of a friction force in a sample problem from Engineering Mechanics, Meriam & Kraige. I will attach a picture for no confusion. http://i.imgur.com/0EdCofi.jpg The Attempt at a Solution Consider only the top...

Homework Statement A tow truck driver hooks up a car to tow it up the hill. The car weighs 1500kg. the cable makes an angle of28 degrees with ground. the cables tension is 1900 N . the static coefficitient is 0.5 and the acceleration is at 6/m s^2 . what is the frictional force on the car...

when a bullet is traveling at great speeds, how will be the frictional and drag forces on the bullet while considering it spinning and then non-spinning. to my knowledge i feel that spinning bullet shows less drag and friction than non-spinning, as we know that the rolling friction is always...

Homework Statement A ladder having uniform density, a length of 3.4 meters and a weight of 121 N rests against a frictionless vertical wall, making an angle of 75 degrees with the horizontal. The lower end rests on a flat surface, where the coefficient of static friction is Mu = 0.400. A...

Homework Statement A parachutist, after jumping from the plane, is accelerating down with average acceleration of 1.6 m/s2 (relative to the ground). What is the force of friction slowing his motion is mass of the parachutist with his equipment is 124 kg? What is the frictional force when the...

Homework Statement A 10.0-kg mass is placed on a 25.0o degree incline and friction keeps it from sliding. The coefficient of static friction in this case is 0.580, and the coefficient of sliding friction is 0.520. The mass is given a shove causing it to slide down the incline. Homework...

Homework Statement A wheel of radius 20cm is pushed to move it on a rough horizontal surface. It is found to move through a distance of 60cm on the road during the time it completes one revolution about the centre. Assume that the linear and the angular accelerations are uniform. The...