Friction force Definition and 235 Threads

Homework Statement A coin is off-center on a turntable which is spinning at a constant velocity. The coin is not slipping. From what I have gathered, the radial acceleration of the coin is caused by the force of static friction on the coin. There is no tangential acceleration. Homework...

Homework Statement At the top of the ramp the body is stopped and then released. It slides down the ramp against a friction force of f= 10 Newtons. Find the body's change in kinetic energy in Joules after traveling a distance s= 3 m down the ramp. Homework Equations There are three...

1. A car with a mass of 1100 kg is being pulled by a tow truck. The tow truck pulls the car to the north with a constant 1200 N force, while a friction force pushes the car towards the south. Starting from rest, the truck pulls the car 60 meters toward the north in 25 seconds. What is the...

Homework Statement An A block of mass 8 kg, is lying over an horizontal table, joint to a bucket of mass 1 kg, by a rope which passes by a pulley. The masses of the rope and the pulley are insignificant. Over the A block is lying a B block, of mass 2 kg. The coefficient of static friction...

Homework Statement A "q" charge particle is moving along +y axis with velocity V0 starting from Origin. A friction force is acting on the charge particle " f= -(alpha)V(Vector) ".A constant magnetic field of magnitude B0 acting along +Z axis. The mass of the particle is m. Find the x...

Homework Statement A frame is made from two beams of equal length joined at the top with a flexible hinge that can open to any angle. A mass, m, is hung by a massless rope from the hinge. The angle between the rope and each of the beams is (phi). Find an expression for the force of...

I just realized I don't even have to do this problem, but I've thought too much about it, and at times like this I tend to be a bit OCD. If someone could just get me started on the right track of thought that would be great! Q: In figure...

Homework Statement A 19 kg block is dragged over a rough, horizontal surface by a constant force of 174N acting at an angle of 34.9 above the horizontal. The block is displaced 54m, and the coefficient of kinetic friction is .233. The acceleration of gravity is 9.8 ms-2. Find the work done...

Homework Statement A 800 N box was pushed up an incline plane of length 4.0m (measured along the incline) to a window ledge 2.0m above ground level. This process required that 3200J of work be done. What was the average frictional force along the plane? Homework Equations W=Fd...

Hey there forum! Consider a damped oscillation in which the friction force is F=-bυ. What I want to ask is how do you calculate the work done by this force for any x interval along a line and what is the Power of the work done by this force? I already know that Power P of the work done...

Homework Statement On a box (of mass "m"), force "F" is applied at "theta" degree angle above the horizontal. The box has static friction coefficient of "u." When this force is applied, and the box remains stationary, what expression describes the frictional force? Homework Equations...

Hi, I am doing a graph on a lab. However, I do not know what information goes where. I have a maximum friction force and normal force from my observations. The sheet tells me to make a maximum friction force vs. normal force graph. Does this mean maximum friction force is on the x-axis and the...

Hi. A friend of mine asked me an interesting question a couple of days ago and I've been thinking for several days but I cannot find a logical answer since I'm not taking any physics course in university. I typed physics forum in google to find the logic of the question and found here. The...

Homework Statement The worker pushes downward and to the left on the box at an angle of 35°. The box has a mass of 135 kg. The box moves horizontally across the floor to the left at a constant velocity. The force applied by the man is 2030 N∠215°. What is the value of the friction force...

Here is the problem I was given: The worker pushes downward and to the left on the box at an angle of 35°. The box has a mass of 135 kg. The box moves horizontally across the floor to the left at a constant velocity. If the force applied by the man is 2030 N∠215°, what is the value of the...

Homework Statement I have a homework question where it asks, "after the spring is compressed and the popgun fired, to what height does the projectile rise from point B? The question is related to an example problem in the book, where the example tells you to solve for "k", which is the spring...

Homework Statement We always encounter this expression: "Friction always opposes the motion". But what does it mean exactly? For example when we push a heavy box and it does not move we consider the friction opposite to the applied force. The second case when the box moves. In this case if we...

There is a "magnetic friction force" in a dynamo? In a rotating dynamo, where the magnet rotates surrounded by a coil, there is something like a "magnetic friction force"? The magnetic field causes an effect similar to mechanical friction, that can slow down the revolving magnet?

Speed & Velocity & Friction Force ? Homework Statement With What Max.Speed? a Car can move in horizontal curve with radius r=25m, if the coefficient of friction is u=0,8 Homework Equations ƒ = μN S= D/T The Attempt at a Solution i tryed bunch of garbages so as i don't...

Homework Statement caculate the force of friction and coefficent of fricition acting on a sliding block given that the acceleration at 3.0 m/s sqaure Homework Equations coefficent of friction = fn/ff force of friction = u fn = u fg The Attempt at a Solution im stuck I am only...

Homework Statement A 15.0 kg box is released on a 30 degree incline and accelerates down the incline at .30 m/s^2. Find the firctiopn force impeding its motion. What is the coefficient of kinetic friction? Homework Equations simga F = ma Force of friction = MU F_N The Attempt at a...

Homework Statement It was on my test yesterday. There is a 10kg block on an incline of 45degrees connected by a string to another block hanging over the side of the incline by a frictionless massless pulley. Kinetic friction on the block on the incline is mu=0.5 The block that is hanging...

Homework Statement A 3.10 kg, 31.0-cm-diameter disk in the figure is spinning at 300 rpm, how much force must a brake apply that is perpendicular to the rim of the disk to bring the disc to a halt in 2.4 s.Homework Equations t=i*alpha wf=0+alpha*t t=fr*sin(theta)The Attempt at a Solution...

1. Suppose that the actual coefficent of friction is one and a half times as large as the value of . That is, . Under these circumstances, what is the magnitude of the force of friction that the floor applies to the ladder? Express your answer in terms of , , , , , and . Remember to pay...

A 21.0 kg box is released on a 36.0° incline and accelerates down the incline at 0.271 m/s2. Find the friction force impeding its motion. F=mg*cos(36) F=21(9.8)*cos(36) F=205.8*.809 F=166.495 I'm not sure what I'm doing wrong. Please help

Homework Statement A grinding wheel of radius 0.330m rotating on a frictionless axle is brought to rest by applying a constant friction force tangential to its rim. The constant torque produced by this force is 72.1 N*m. Find the magnitude of the friction force. I'm honestly lost at even...

Can anyone tell me why net Force of x-component = -f(k) in a moving puck? I don't get how the net Force of x-component be just the kinetic friction force. What about the force that the puck is using to be actually moving? shouldn't that force be included in the net Force of x-component...

Homework Statement A heavy box (200.0 kg) is sitting still on a warehouse floor, despite the efforts of a worker to push it (with a force of 300.0 N). If the coefficient of static friction between the box and the floor is 0.6, what is the friction force between the box and the floor? What is...

Homework Statement A 13.0 box is released on a 32 incline and accelerates down the incline at 0.10 . a) Find the friction force impeding its motion. b)What is the coefficient of kinetic friction? Homework Equations The Attempt at a Solution

Hey guys i was told to calculate the frictional force of a ball bearing when it slide across a track. I was given the initial and final velocities , the distance between them and the weight of the ball. The 1st thing i though of was V^2 = u^2 + 2as and calculate for the deceleration then equate...

How do we set up the normal and friction force at the place where the ladder (the red line) touches the corner? http://img56.imageshack.us/img56/6655/prob08021sketch01.gif Worked Done So Far I used a normal force the headed off to the top left at 45 degrees and a perpendicular friction force...

Homework Statement A toy train moves along the track at 9.0m/s. When the power is turned off, the train comes to a stop in 6.0s. The net force on friction acting on the train to stop it is Homework Equations F=ma The Attempt at a Solution how do i find mass and acceleration so...

Homework Statement A block of mass m lies on a horizontal table. The coefficient of static friction between the block and the table is mu_s. The coefficient of kinetic friction is mu_k. (mu_k<mu_s) a: Suppose you push horizontally with half the force needed to just make the block move. What...

Homework Statement Hi guys, i am sort of confused with the concept of slipping. I got a question.. what does it mean by maximum friction force before slipping occurs? Homework Equations I believe in the use of f_{}s \leq \mu_{}sn The Attempt at a Solution please correct me if i am wrong...

Homework Statement A 2.5 kg block is initially at rest on a horizontal surface. A horizontal force F of magnitude 6.0 N and a vertical force P are then applied to the block (the vertical force is upwards). The coefficients of friction for the block and surface are Ms = 0.40 and Mk = 0.25...

Homework Statement For a touring bicyclist the drag coefficient C(where f of air = 0.5CApv^2) is 1.04, the frontal area A is 0.462 , and the coefficient of rolling friction is 4.60×10−3. The rider has mass 53.0kg, and her bike has mass 11.1kg. Note: p is density of air (1.2kg/m^3) To...

Homework Statement A 21.0 kg box is released on a 38.0° incline and accelerates down the incline at 0.267 m/s2. Find the friction force impeding its motion. Friction force is correctly calculated as 121N Homework Equations Ffr = \muFN (Friction force equals mu times normal force, in...

1.Quick question: a 12kg mass is on a 30 degree incline where the coefficient of static friction is 0.8. What is the friction force exerted on the mass? 2. F = ma, f = uN 3. I got around 83 N for this. All I did was multiply the coefficient of friction by normal force, which...

Homework Statement A uniform hollow spherical ball of mass 1.75kg and radius 40.0cm rolls without slipping up a ramp that rises 30 degrees above the horizontal. The speed of the ball at the base of the ramp is 2.63m/s. while the ball is moving up the ramp, find the acceleration of its center...

How to specify the direction of Friction force , Hello, Could you tell me how to specify the direction of the friction force ? For example see the question below, I couldn't solve the question http://img291.imageshack.us/img291/7808/25857191iu3.png

Homework Statement A force of 30 N accelerates a 5.0-kg block at 5.0 m/s2 along a horizontal surface. How large is the frictional force? (b) What is the coefficient of friction? Homework Equations I am not relly sure of the equations used.. The Attempt at a Solution Well...

Homework Statement A 380 g cart is rolling along a straight track with velocity 0.850i m/s at x = 0. A student holds a magnet in front of the cart to temporarily pull forward on it, and then the cart runs into a dusting of sand that turns into a small pile. These effects are represented...

Homework Statement At a local hockey rink, a puck with a mass of .12kg is given an initial speed of 5.3m/s. If the coefficient of friction is .11, what distance does the puck slide before coming to rest? Homework Equations F(net)=ma, F(friction)=Coeff. x F(normal) The Attempt at a...

hello everbody...i got two question about kinetic friction force... tat is 1. is kinetic friction force of an object always the same value?as the formula kinetic friction force = coefficient of kinetic friction force*normal , coefficient of kinetic friction force is always the same...is me...

With all the mechanical forces in statics problems I can assume the sense and I might get a negative answer which implies I made the wrong assumption. But why can I not do this with the friction force when using the equation F=uN?

2 blocks are accelerated across a horizontal frictionless surface as shown in a diagram (block on block getting pulled by a force, larger block on bottom). TH friction forces keep the 2 blocks from sliding relatice to each other, and the two move witha same acceleration. If F= 13.00 N, m1= 3.500...

Hey guys this is a practice problem for my lab and i can't get it can someone please help: The force sensor measures the force on the sensor due to the bumper, but the cart's momentum change arises from the force on the cart due to the bumper. Which of the following facts are needed to assert...

Block A in the figure weighs 64.2N . The coefficient of static friction between the block and the surface on which it rests is 0.30. The weight is 11.3N and the system is in equilibrium. The picture is a block A, sitting on a table. A string is attached horizontally and then the string...

A village maintains a large tank with an open top, containing water for emergencies. The water can drain from the tank through a hose of diameter 6.15 cm. The hose ends with a nozzle of diameter 2.35 cm. A rubber stopper is inserted into the nozzle. The water level in the tank is kept 7.50 m...

Homework Statement http://img337.imageshack.us/img337/2514/diagramfn4.png The Attempt at a Solution \sum F_{x} = w_{x} - T = m_{x}a T = (6.9)g - (6.9)a \sum F_{a} = T - w_{a} - f_{s} = m_{a}a T - m_{a}g - m_{a}a = f_{s} (6.9g - 6.9a) - m_{a}g - m_{a}a = f_{s} I don't see a 5kg...