Friction Definition and 998 Threads

1. The problem: A hockey puck is hit on a frozen lake and starts moving with a speed of 11.6 m/s. Five seconds later, its speed is 7.4 m/s. What is its average acceleration? The acceleration of gravity is 9.8 m/s. Answer in units of m/s. What is the average value of the coefficient of kinetic...

Homework Statement A block is placed on a inclined plane. The incline of the plane is 21° .A 24 N force is required to push the block up the incline with constant velocity. The force is applied at an angle of 15° as shown in the picture. The coefficient of kinetic friction (μk) is 0.26. What...

If a wheel is freely rolling on the ground (not torque driven, but by a force acting on its center of gravity) towards the right, the friction force on the bottom of the wheel would be acting towards the left. What if the friction force was equal to the force acting on the wheel's COG? Then the...

Homework Statement A homogeneous semicircular disc of mass m and the radius r is released from rest in the vertical position shown in the figure. Determine a minimum value of the coefficient of friction μ between the disc and the horizontal surface that prevents sliding in the initial moment...

Homework Statement Homework Equations Cf=0.0577(μ/xρUm)0.2 The Attempt at a Solution I've managed to do parts a) and b), however I don't believe my attempt at the first part is correct as I am using a different Cf than the value used in the mark scheme. The expression I made for the first...

Homework Statement For my Physics lab this is what my teacher handed me... I have no idea how to attack the situation, can someone help solve? Devise a procedure for an experiment which will measure the coefficient of kinetic friction between a block of unknown mass m and the table, where the...

Dear All, I am looking for a method to calculate the friction stresses created in 1 mm thick, fully supported, slide of soda-lime silica glass. In this experiment a 1/4" ball bearing of various metals is being translated over the glass surface under a constant load of 2000g. The glass slide is...

Homework Statement ##m=1[kg]##, ##M=5[kg]##, ##u=0.6## Calculate the minimum force required for the blocks to remain in the same position thourought the motion. For the part a) there is no friction between block 2 and the floor, for the part b there is and its ##u_f## Homework Equations 3...

Homework Statement A cart with mass M has four wheels (idealized as uniform discs), each of radius r and mass m, arranged symmetrically with respect to the cart. Find the acceleration of the cart when a horizontal force F is applied on it. There is no slipping between the wheels and the...

Hi, I'm trying to program a simple physics engine from scratch as an exercise, and I'm starting with manipulating a stick with the mouse pointer. As of now, it dangles from one end demonstrating simple pendulum physics. Now, I want to add a friction component to the "axle" it's rotating on to...

Homework Statement A small block is on the point of slipping down a rough ramp inclined at 35 degrees to the horizontal. a) What is the coefficient of static friction between the block and the ramp? Answer μ_s = 0.70 b) The ramp is attached to the edge of a 0.8 m high table. After the block is...

Homework Statement A 2.00-kg aluminum block and a 6.00-kg copper block are connected by a light string over a frictionless pulley. They sit on a steel surface as shown in Figure P5.64, where theta= 30.0°. When they are released from rest, will they start to move? If so, determine (a) their...

Homework Statement We have a box has W as widht and h as height.Now when we push it on top of it, it does not slide but the side is closest to us is lifting. We consider center of the mass in center. Homework EquationsThe Attempt at a Solution I think the reason of lifting just one corner is...

https://lh3.googleusercontent.com/0GOyZeQMdpLgYxYwwP4FMabe-Mk7QpADPC4ZK4PVpBGKvamcqjopOf3M0evdhE8PHZ3iTQ=s138 m1 is 4 kg and m2 is 8 kg. The kinetic friction coefficient on the table is 0.3. m1 is held in place. When m1 is released, m2 accelerates 1.2 m to the floor. Use conservation of...

I have been trying to find the speed of a point mass sliding with friction (f=μN) in a hemispherical bowl. Start at the top at rest. So far I have -μN+mgcosθ=ma and N=mgsinθ+mv2/R where θ is the angle below horizontal from the center of the sphere and R is the radius of the sphere. I know it...

Hi, let me ask probably dumb questions to physics experts... Why does the cue ball goes almost straight when its right (or left) side is struck by a cue (right English)? This is quite different from when a ball hits another ball, in which case the ball goes almost perpendicular from the contact...

Homework Statement In a lab assignment we created a Fletcher's trolley system and were asked to calculate the normal force, the force of friction, and then create a graph of both to find the coefficient of kinetic friction. So far, the variables I have are: Hanging mass: 0.100 kg Sliding...

A cylinder rolls on a horizontal, flat surface without sliding towards the left, so it must be rolling anticlockwise about its center of mass (CM). Suppose it slows down to a stop due to friction. What is the direction of the friction at the point of contact? Since it slows down, friction must...

Homework Statement A block sitting on a flat surface has a us of 0.5. The normal force acting on the block is 10N. If someone pushes the block with a horizontal force of 2N. What is the static friction force acting on the object? Homework Equations F=ma fs=usR (less than or equal to)The...

Homework Statement Box B is on top of box A. Box A has a mass of 1 kg, B has 0.3 kg. Coefficient of friction between ground and box A is 0.5, between box A and B : 0.75. With what maximum force can I pull box A without box B sliding back ? m1 = 1 kg m2 = 0.3 kg u1 = 0.5 u2 = 0.75 Homework...

Homework Statement A block is being pushed off the table by a spring. Explain the path of motion of the block if there is friction and if there is no friction. Homework Equations N/A The Attempt at a Solution The block with friction will have a lower velocity than its non friction counterpart...

The situation is part of a mechanism I have been working on. It is used for a bicycle to automatically store and release energy with a spring. It is somewhat similar to a car clutch. Homework Statement Two friction discs are rotating with different angular velocities and different torques. The...

according coulomb force of friction is independant of contact surface a tyre car grip goes in function of contact surface and grip is caused by friction this seems contradictory with coulomb is still coulomb view mainstream or has it been corrected?

Homework Statement With the equations of motion in polar coordinates given by ##r(t)=pcos{kt^2}, φ(t)=kt^2## determine the velocity intensity of a point ##M## on the circumference of a cylinder which is rolling without friction on a horizontal plane at time ##t## is the velocity of the center...

Homework Statement A small block of mass 1.74 kg rests on the left edge of a block of length 3.05 m and mass 7.95 kg. The coefficient of kinetic friction between the two blocks is 0.279, and the surface on which the 7.95 kg block rests is frictionless. A constant horizontal force of magnitude...

Homework Statement A 55.0-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.300. A force of 156 N is applied to the box directed at an angle of 18.0 above the horizontal. Does the box move? Please help??The Attempt at a Solution 156...

Homework Statement A piece of butter is sliding down a warm roof. It is known, that on contact, the friction decreases to one tenth per 5 seconds. Not taking into count the fact that the mass reduces due to melting, how can you create the equation for the changing friction, that takes into...

Hello all, I have browsed this forum occasionally when I had questions and threads showed up on a search. I have been stumped by a problem, so I decided to create an account and see if anyone could help me out! 1. Homework Statement A coal barge 1000 ft long and 100 ft wide is submerged in a...

Homework Statement A 60 kg farmer ropes a 300 kg ox. Both are initially at rest, 24 m apart on a frictionless level surface. When farmer ends up pulling the ox towards him, the ox will move A) 4m, B) 5m, C) 12m, D) 20m, E) 24m . Can anyone help me solve this? Homework EquationsThe Attempt at...

hi everyone! I'm new here. I was wondering how energy can be lost to friction? How would one even calculate that? Thanks!

Homework Statement So here is the Problem: A big truck (m=50t) is going at 100km/h. Now the truck can't brake anymore and Superman comes to aid. He (has a mass of m=100kg) tries to stop the truck while he is wearing shoes with a rubber-texture and a friction coefficient of µ = 0.8. Assume that...

Homework Statement If the incline of the driveway is 19 ∘ from the horizontal, what must the minimum coefficient of static friction be between your shoes and the ice? Homework Equations Fs=uN The Attempt at a Solution

I have been stuck on this physics question: An object is sliding along a flat surface with an initial speed of 30 m/s. What must the coefficient of kinetic friction be between the object and the surface if the object slides to a stop in 10m? What would be the speed of the object after it had...

Hi, I'm simulating the behavior of a car and I have some troubles with the tires. Specially with slip when the car is accelerating. I've seen many documents over the internet and I understood 2 main things: Wheel slip is necessary to accelerate & the coefficient of friction depends on the slip...

Homework Statement A 10 kg initially at rest is pulled 13m across a floor by a 50N force. if friction does 380J of work over this distance, what is the block's final velocity? http://imgur.com/a/zM1MX Homework Equations W=Fd, Ek=1/2mv^2 The Attempt at a Solution Since the block was at...

Homework Statement How much work is done by friction when a box with an apparent mass of 325kg moves horizontally across a floor with coefficient of friction of .33 and is pulled at 59.9 degree angle for 2.60 m? What is the force that is pulling the box? Homework Equations W=Fdcos@ (@= theta)...

< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > Hi! We are looking for alternative ways to heat up flat iron without using electricty or fuel or solar panel. So we came up with friction (as it is also a source of heat). But we don't know...

I recently posted a question on similar line and got few good explanations as well. Still, I am unable to understand clearly. Hence I am going more specific this time. In the given picture taken from internet, friction force acting between an inclined plane and an object is defined as Fr = W x...

Homework Statement System comprised blocks, a light frictionless pulley and connecting ropes (see diagram). The 9.0kg block is on a perfectly smooth horizontal table. The surfaces of the 12kg block are rough, with μk = .2 between the two blocks. If the 5.0 kg block accelerates downward when it...

Homework Statement A uniform ladder leans against a smooth vertical wall. If the floor is also smooth, and the initial angle between the floor and the ladder is theta(0), show that the ladder, in sliding down, will lose contact with the wall when the angle between the floor and the ladder is...

Homework Statement 100 kg box is held in place on a ramp that rises at 30° above the horizontal. There is a massless rope joint to the box that makes a 22° angle above the surface of the ramp. Coefficients of friction between the box and the surface of the ramp are μk = 0.40 and μs = .60. The...

Hi there, Suppose we had a car going in a circle. We know that the turning angle(angle between the movement direction and the wheel axis) and the friction are connected, because friction determines the centripetal force and it determines the radius of the circle that we make with our car. I need...

Homework Statement Hi, we had a Lab Activity on the Coefficient of Friction, but right now I am really confused and stuck. Since the teacher used an online resource, we are supposed to make two graphs based off the data and it's very unclear and unhelpful. :( I can't seem to find anything at...

Hi, Recently I came across this image in deriving an equation for angle of repose of an object in an inclined plane: "W" is the weight of the component which acts vertically down. "Rn" is the normal reaction by the inclined plane "W cos alpha" is the component of the weight of the object...

Homework Statement A shot putter with a mass of ##80## kg pushes the iron ball of mass of ##6## kg from a standing position accelerating it uniformly from rest at an angle of ##45^{\circ}## with the horizontal during an interval of ##0.1## seconds. The ball leaves his hand when it is...

I raced a toy car on a wooden plane alongside an ice cube on a block of ice in my kitchen today. the ice cube combo won every time even allowing for my crude starting gate. most texts I have seen introduce dynamics of inclined planes with a bead on a wire or more common a block on a...

Homework Statement A football player (90 kg) moving east collides with another football player (80 kg) moving north. When both players collide, a helmet (2 kg) is ejected south at a velocity of 5 m/s. If both players fall to the ground and slide a distance of 2 m North-East with a friction...

is "stickyness" part of the static friction? is it already integrated in coefficient of static friction μ or there is some special case where you put "coefficient of stickyness" in formula μ*N when things get sticky? I imagine peace of tape on some flat, relatively smooth surface. you have to...

Homework Statement The coefficient of static and kinetic friction is constant for a specific surface. On an incline plane s and k are both equal to tan of the inclined angle. If the angle increases then tan changes which means the coefficient of friction changes. How is this so? Homework...

if i heat up my drill bit before drilling, will that result in less coefficient of friction between the drill bit and wood material or metal material? and if so yes will it give me more time before the drill bit wears out because of high temperature as it will be harder to reach high temperature...