Friction Definition and 998 Threads

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...

Homework Statement A rope attached to a 19.0 kg wood sled pulls the sled up a 19.0° snow-covered hill. A 14.0 kg wood box rides on top of the sled. EDIT: the actual question to be answered, oops. What's the magnitude of the tension that will cause the box to slide? Mass of box (mb) = 14.0kg...

Homework Statement A child slides down a slide with a 28 degree incline , and at the bottom her speed is precisly half what it would have been if the slide had been frictionless. Calculate the coefficient of kinetic friction between the slide and the child. Homework Equations Newtons second...

Homework Statement A child slides down a slide with a 28° incline, and at the bottom her speed is precisely half what it would have been if the slide had been friction-less. Calculate the coefficient of kinetic friction between the slide and the child. Knowns: 28° speed=V/2 Homework Equations...

1. It makes sense that air drag increases with speed, but is it a direct increase or to the square of the velocity? (so the faster you go the more energy wasted?) 2. What is the relationship between air temperature, pressure, and air drag? I can see how on a warmer day the molecules are further...

Homework Statement A block of 10 kg is pulled by a force of 100 N at and angle 30 degrees above the horizonal through a distance of 4 meters. Kinetic friction has a coefficient of 0.3. How much work does friction do in that distance? If its speed is 3 m/s at point a, what is its speed at point...

https://scontent-dft4-1.xx.fbcdn.net/v/t35.0-12/14796269_10210868496286479_1115393743_o.jpg?oh=0ccd692c60a1d0bab84d5fbaf7e6197b&oe=580A1894 In the figure, a 6-kg box is sliding up an incline that makes an angle of theta=30 degree (with respect to the horizontal). As it slides up the incline, a...

Homework Statement a 10 kg box is moving on a level floor. The coefficient of static friction between the box and floor is 0.3. What is the force of kinetic friction? Homework Equations fk = FN * μk The Attempt at a Solution I rearranged the formula so that everything was set equal to the...

When reading lessons on the conservation of momentum, you usually see examples with colliding balls or something to that effect. These examples always seem to fail to mention friction. These balls will always come to a stop due to friction. How is momentum conserved when it is lost to friction...

Homework Statement During a flume ride the boat plunges 54 feet down a 43 degree incline. Assuming coefficient of friction .12 determine the acceleration of the boat.[/B]Homework Equations I'm really not sure, no mass is given or force. All of the equation I know involve mass or force. The...

Homework Statement "A rope is used to pull a ##\frac{357}{100}kg## block at constant speed ##\frac{203}{50}m## across a horizontal floor. The force on the block from the rope is ##\frac{768}{100}N## and directed ##15°## above the horizontal. What are (a) the work done by the rope's force, (b)...

Homework Statement There is an example problem in a textbook I'm looking at where they solve a simple incline-mass problem (friction included) using work-energy. We are given the mass 40kg, the length of the slide is 8 m, the incline is 30 degrees, the coefficient of kinetic friction is .35...

Two questions I had: 1. How is the force of friction of the tires pointed inwards to cause centripetal acceleration? If the tire is rotated when trying to turn, the car is still traveling with a velocity perpendicular to the circle and force of friction would still be counteracting the...

Homework Statement 2 Blocks connected by a string is placed on a rough horizontal floor,the coefficient of friction for block 1 is 0.2 while for block 2,it is 0.1. A force of 8N is applied on block 1 and a force of 1N is applied on block 2.Find the tension in the string and the frictional...

In the tablecloth trick, if we pull the tablecloth with a great force, the objects on it will stay on the table. But, if we pull it gently, the objects on it will still get along with the cloth movement. I know that if the force exceeds the maximum value of static friction, the objects will...

I'm a bit confused. We all know that rolling with slipping is associated with kinetic friction. But Is that friction due to the traslational motion of the center of mass or just the spinning motion?If friction exists because of the translational motion, then in theory, I can slowly lower a...

While in class, my Thermodynamics professor came up with an interesting fact, that neither I nor my colleagues were ever aware of: While you may have heard that friction influenciates the movement in Newtonian Mechanics, no one really knows what friction is. And so I have been wandering why it...

Suppose there are a number of objects on top of each other and the bottom one being on top of a frictionless surface. The masses of all of them are given. The coefficients of friction between all surfaces of contact are given. And, the forces acting on each block are given (It's not necessary...

1.Question: A penguin is going down a slide. The coefficient of kinetic friction between the penguin and the slide has a value of 0.77. It takes three times as long to slide down this slide as it would if the slide were frictionless. Find the angle of the slide. 2. My answer: I chose solving it...

Homework Statement A weightless string passes through a slit over a pulley. The slit offers frictional force '##f##' to the string. the string carries two weights having masses ##m_1## and ##m_2## where ##m_2 \gt m_1##, then find the acceleration of the weights. Homework Equations...

Homework Statement A force F is applied to a box of mass M at an angle θ below the horizontal (see figure). The coefficient of static friction between the box and the floor is μs, and the coefficient of kinetic friction between the two surfaces is μk. a) What is the minimum value of F to get...

Homework Statement At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails weigh 10kg and 20kg, respectively, and are the same size. If the...

Hello all I'm trying to calculate a torque needed to tighten a threaded terminal. (Both male and female parts are copper alloy) I'm using Motosh's equation which requires me to use the coefficient of friction. Web sources tells me that the copper-copper coefficient of friction is 1.0. The...

Homework Statement Determine the smallest force P that will cause the spool to have impending motion. Homework Equations Equations of equilibrium, and static frictional equations. ##ΣFx = 0;## ##ΣFy = 0;## ##ΣMb = 0;## ##Fsa = μNa## ##Fsb = μNb## The Attempt at a Solution My first...

1. Homework Statement A block of mass 1.60 kg is connected to a spring of spring constant 152 N/m which is then set into oscillation on a surface with a small coefficient of kinetic friction. The mass is pulled back 34.6 cm to the right and released. On the first right to left oscillation...

Homework Statement the main question asks: "If the book is initially at rest, what is its speed after it has traveled 0.400 m up the wall?" Homework Equations ∑F = m*a vf2 = vi2 + 2 * a * d , when initial velocity is 0. The Attempt at a Solution So here's my free body diagram: and out of...

First time posting on the forum - I've been coming here a lot the past year or so to seek answers. This one is concerning a lab. I think I've already done the legwork but am sort of looking for either something I'm missing or a confirmation of sorts. It's pretty messy and wordsy but if you...

Friction is independent of area of surfaces in contact as long as the normal reaction remains the same.I agree that it does not depend and so says it's formula but the condition that it does when the normal reaction remains same looks odd to me..Can someone help me out to understand this?

Hi guys, I am curious to find if there is any invention where the friction between the surface of motorway and cars' tyres are used to create kinetic energy which can be converted into electrical energy to power up the houses and plants around them. Thank you.

Homework Statement Mass MA = 4 kg rests on top of mass MB = 5 kg that rests on a frictionless table. The coefficient of friction between the two blocks is such that the blocks just start to slip when the horizontal force F applied to the lower block is 27 N. Suppose that now a horizontal force...

Homework Statement A man with mass ##M## has its string attached to one end of the spring which can move without friction along a horizontal overhead fixed rod. The other end of the spring is fixed to a wall. The spring constant is ##k##. The string is massless and inextensible and mantains a...

Homework Statement Board ##A## is placed on board ##B## as shown. Both boards slide, without moving w.r.t each other, along a frictionless horizontal surface at a speed of ##6 \text{m/s}##. Board ##B## hits a resulting board ##C##, "head-on". After the collision, board ##B## and ##C## stick...

Homework Statement A man of mass ##80## kg, stands. on a horizontal weighing machine, of negligible mass, attached to a massless platform P that slides down a ##37^{\circ}## incline. The weighing machine reads ##72## kg. Man is always at rest w.r.t weighing machine. Calculate: (a) The...

Homework Statement The brick mass 500g is pushed on hill with velocity 200 cm/s, how far can the brick reach before it stops when μ=0.150 Homework Equations W=Fdcosθ E=1/2mvv The Attempt at a Solution I got about 1 m before the brick stops, does it correct?

Homework Statement Find the mass of the object which is being pulled by 40 hp engine with a constant speed 15 m/s (μ = 0.15) Homework Equations P=Fv F=μN The Attempt at a Solution I got about 1,350 Kg for the answer but I don't know why P=Fv( It is just included in the problem ) First, I...

Homework Statement A 500 g block lies on a horizontal tabletop. The coefficient of kinetic friction between the block and the surface is 0.25. The block is connected by a massless string to the second block with a mass of 300 g. The string passes over a light frictionless pulley. The system is...

Homework Statement "When the three blocks in Fig. 6-29 are released from rest, they accelerate with a magnitude of ##0.500 \frac{m}{s^2}##. Block 1 has mass M, Block 2 has mass 2M, and Block 3 has mass 3M. What is the coefficient of static friction between Block 2 and the table?" Homework...

Homework Statement I think I am lacking some concept. I can't solve this one: There are three blocks of masses 2kg, 3kg and 7kg lying on a frictionless table with the 7kg block on bottom 3kg in the middle and 2kg on the top. A horizontal force of 10N is applied on the bottom block. The...

Homework Statement Three blocks A, B, and C of masses m1, m2 and m3 respectively are lying on top of each other on a frictionless table with A on top and C on bottom. The coefficient of friction between A and B is u1 and between B and C in u2. Find the accelerations a1, a2 and a3 of the three...

What does the line in the rectangle box means? (What is the difference between limiting friction and centripetal frictional force?) What type of motion is meant by skidding? http://prnt.sc/c7ptm8

Suppose two rigid circular coins are lying on top of each other. A horizontal force on the top coin is applied. So, I think there are two possible scenarios: 1. Both move together with common acceleration (if friction between them is strong) 2. Only the top coin slips over the bottom (if...

As far as I know both the friction or the frictionless contact types in Ansys doesn't prevent motion in the perpendicular direction. I have been following this tutorial https://goo.gl/w8sIlG (no need to open) but I have found something strange when I do the same but without changing the analysis...

Homework Statement We did a Prac where we attached ticker tape to a cart (905g), and the cart to a mass (249g) through a pulley. We then had to assess the tape and answer questions. We are asked to calculate the force acting upon the whole system and then calculate the force acting only upon...