Friction Definition and 998 Threads

I have conducted an experiment that measures the velocity of an object that is moving on a flat surface. The object rolls on four fixed caster wheels. The wheels are made of some kind of rigid material. Maybe nylon, maybe hard rubber. The total mass of the object, including the wheels, is...

Homework Statement I can't understand why friction acts radially inwards when a body is rotating on a rough turntable. If the friction is removed, the body would move tangentially, hence it has slipping tendency tangential, not radially outwards, then shouldn't friction act tangentially...

I created this example to see if i can explain how humans walk but I can't. If I'm correct, when we push the ground to move forward we apply a force with the opposite direction (backward). Let's name this force Fp (for push). Because of that force, a friction force is being applied to us with...

I read an article where the author tried to find the maximal speed a car can have when taking a turn of certain radius. They represented the car as a point and claimed that the force of friction is the centripetal force - acting perpendicular to the trajectory of the car. I do understand why...

Hi, first of all sorry... I know (close to) absolutely nothing about physics except from what I remember from school a looong time ago... :-). So, my question might sound a bit silly here. But thanks a lot for taking you time already! Homework Statement In retail business there is some...

Homework Statement A speed of a body of mass 8 kg is 6 m/s in position A. By the time it gets to B, the speed is measured to be 12 m/s. What is the frictional force opposing the motion? The incline is 30 degrees, the height of the ramp is 12 meters. Position A is at the top of the ramp...

How do i suppose to determine the uncertainty for the slope of my Static friction against normal reaction graph? My data for static friction and normal force has the uncertainty of +/- 0.0001 The uncertainty is too small for me to draw airbox/bar in the graph to draw the max and min slope...

Hello Guys, I have been pondering on the nature of the frictional force and its dependency on the area of contact for the past few days and I had already searched for plausible explanations for the same.Although I could gather a few discrete points ,I couldn't get a complete picture of it. Some...

What makes frictional force the centripetal force of a car turning along a curve? As friction is the opposing force and acts anti-parallel so there is no component of frictional force towards the center,right? Then how can frictional force be centripetal force?

Homework Statement A block m2 is placed on a surface where the coefficient of friction is μ2 and another block m1 placed over the block m2 where the coefficient of frictio is μ1. A force F=k*t(Force as a function of time),is acting on the block m2. Now my question is that when would the...

I am working on a design where I have a block which has a cap assembly fitted to it - see images attached. The cap assembly is constructed of: - Main body with two holes through (flowing water in and out) - Locking ring with a threaded outside, grooves for tightening by hand and two o-rings...

So say I've got a wheel who's outer radius is 12" and the radius of the axle is 1.5", so the simple machine here is an 8 to 1 ratio. So I am wondering, since 1/2mv^2 is for kinetic energy, and the velocity here is 1/8th, does it mean the friction is 1/8th or 1/64th? does it get 1/8th hotter or...

When we loose the touch with ground no friction is acting..so how we accelarate ? also friction prevent our foot from sliding but also accelarates our body ? how is it possible to acting in 2 different points ( foot and center of mass ) ?

I am currently working on designing a linear brake/lock for a completely different purpose but it will be based on the same principle as in a quick clamp shown below. Before building a prototype I do want to make some rough calculations to check dimensions, angles etc. etc. However, I am for...

Homework Statement A long plank of mass M rests upon a smooth horizontal surface. A thin circular ring (m, R) slips (without rotation) upon the plank with initial velocity v(i). The coefficient of friction between the wheel and the plank is C. at time t, the ring stops slipping and pure rolling...

Hi, I'm making an electric longboard and trying to write an app for my phone to function as the remote. I've got a bunch of fancy Star-Trek-esque indicators on it, one of which is the pitch and roll of the deck. All the indicators have "danger zones" and turn red when they hit them, and for this...

Homework Statement You gradually apply a force to a 10. kg wood block on a wood table. What will the applied force on the block be once it is moving? The coefficients of static and kinetic friction are 0.5 and 0.3, respectively. The acceleration due to gravity is 9.8 m/s2. Homework Equations...

Homework Statement A person is pushing a box. The net external force on the 60 kg box is stated to be 90 N. If the force of friction opposing the motion is 30 N, what is the acceleration of the box? Homework Equations This seems to be a pretty easy, straightforward problem, but I'm confused...

Homework Statement The speed of a 4.0-N hockey puck, sliding across a level ice surface, decreases at the rate of 0.61 m/s2. The coefficient of kinetic friction between the puck and ice is: A) 0.062 B) 0.25 C) 0.41 D) 0.62 E) 1.2 Homework Equations I'm not too sure but i know that : If the...

So I've done a practical investigation. Pretty much I used a elastic band to launch a puck on a horizontal floor. I have measured the extension and force for the elastic band, and the extension and stopping distance for the puck on two different surfaces. How do I calculate the coefficient of...

Homework Statement A crane is moving two equally spaced masses to the roof. One box is 10kg and the other box is 20kg. As the plank tilts towards the 20kg box, at what angle will each box begin to slide? The coefficient of static friction is 0.4 Homework Equations Newton's second law, Fnet=ma...

Homework Statement A block of mass 20kg is on rest on a rough plane inclined at 60 degrees to the horizontal. A force P is applied to the block to "maintain equilibrium". P is parallel to the line of greatest slope of the inclined plane. The maximum value of P is twice the minimum value of P...

It's really confusing if the frictional force IS an external force.. My guess is the frictional force isn't an external force and therefore I can observe the momentum conservation even with friction if I carefully measure the velocity right before and after the collision. But I'm not sure about it..

Homework Statement A satellite of mass m_s orbits the Earth in a circular orbit of radius r_0. If the satellite orbits at the upper part of the atmosphere and the friction force f is constant, it would trace an spiral and fall to the earth. but if we suppouse that the friction force is small...

Homework Statement A person is running on a track. Which of the following forces propels the runner forward? a) The normal force exerted by the ground on the person b) the normal force exerted by the person on the ground c) the force of friction exerted by the ground on the person 2. Homework...

Homework Statement A block of mass M is at rest on an incline that makes angle theta with the horizontal. Given that the static coefficient of friction is mu_s1 and the kinetic coefficient friction mu_k, what is the magnitude of the force of static friction exerted on the block by the incline...

Hello everyone, I recently realized that knots in ropes and shoe laces are possible because of the friction between the rope fibers. I guess if friction was not present the knot would just not work, i.e. a knot would still form but not be tight... What are some other interesting examples of...

Homework Statement An object is placed on a slope with initial velocity v=0m/s. Angle of the slope is 30 degrees and the coefficient of friction (or friction factor, not sure how it's said in English) is given as u=0.1*(x/m) where x is the path traversed and m is the mass of the object. After...

Homework Statement Ladder leans against wall at angle θ. It is L meters long and mass m. Find the coefficient of friction with the floor. Assume no friction at the top.[/B]Homework Equations ΣFx = 0 ΣFy = 0 Στ = 0 ƒ = μFn (Fn being the normal force with the ground) The Attempt at a Solution...

Homework Statement Two block M1 and M2 rest upon each other on an inclined plane. Coefficient of friction between surfaces are shown. If the angle θ is slowly increased, and M1<M2 then Options : 1- Block A slips first. 2- Block B slips first. 3- Both slip simultaneously. 4- Both remain at...

Homework Statement If you have an object say in a vertical pipe, which only has a gravitational force acting on it would the reaction forces only be friction forces? If this is the case how would you calculate the forces? would you calculate the friction force using the friction coefficient or...

Hey guys! Can anyone tell me how to calculate the force of air friction on meteor that's going to impact

Homework Statement Homework Equations The Attempt at a Solution I've spent so long trying to solve this system of equations with my calculator that can do this for me. But, somehow , i still don't get it.The equations i got are: 1st diagram Fc - Nb =0 Nc -0.3Nb -300=0...

Homework Statement Hello; I have as shown in the picture, a rope (in green), this rope is located between a support A and a support B. The Support A doesn't move and attached to the ground. The support B apply a force F1 against the rope, this force is made by a helical compression spring...

A steel washer is suspended inside an empty crate from a light string attached to the top of the crate. The crate slides down a long ramp that is inclined at an angle of 37 above the horizontal. The crate has mass 154 kg. You are sitting inside the crate; your mass is 61 kg. As the crate is...

Wouldn't the chain easily get caught on a rock or something? And how does metal provide more traction than rubber wheels?

Homework Statement The coefficient of kinetic friction between a 3.5kg bowling ball and the ice on a frozen lake is very small: μ= 0.02. If the ball is bowled on the ice with an initial velocity of 16.5ms^-1, how far will it travel before friction brings it to rest? Homework Equations Fn=mg...

Homework Statement Three identical 4 kg crates are stacked one on top of the other. You want to accelerate them as much as possible by pushing on the lower crate, but the forces of static friction between the surfaces of the crates max out at 25 N. What is the maximum acceleration you can...

Homework Statement There is a metal stick that is connected to the ceiling with another one. The angle between them is 60°. Calculate the friction. Both lengths and weights are the same. Homework Equations T = f N or actually none, except trygonometry The Attempt at a Solution I tried using...

Homework Statement I need to find the coefficient of kinetic friction from a set a lab data that I found. I had a mass connected to a mass hanger by a pulley, and measured the acceleration of the mass with various amounts of mass on the hanger. In the attached image, the acceleration was...

Homework Statement A 1450-kg car is towing a trailer of mass 454-kg. The force of air resistance on both vehicles is 7471N[backward]. If the acceleration of both vehicles is 0.225m/s^2[forward], what is the force of static friction on the wheels from the ground? Homework Equations Fnet = ma...

1. Homework Statement i did part a,b,c but i am confused about part d.. i have a test tomorrow and will reattempt this when i wake up but i really need a hint here..so when the worker pulls upward he is decreasing the magnitude of -mg right? so if Fn and mg initially cancel each other out...

1. Homework Statement in picture Homework EquationsThe Attempt at a Solution in picture, not sure if i am even doing this properly but i think i am? i am going to continue trying part b but please if you can let me know if i am doing this proper let me know...Thank you

1. Homework Statement I have already solved this one weeks ago, and i have a test Tuesday so i was reviewing these problems. I understand everything when solving with 60N as the force.. but then when i changed the force to 20N, i had to use the coefficient of kinetic friction to get the correct...

Hi , The Static Friction force of an object on a ramp(inclined plane) making an angle with the horizontal is greater than the weight component down the ramp. My textbook says that this means that the object on the ramp is stationary as the frictional force is greater than the weight component...

Homework Statement A child of an Eskimo decided to slide down an igloo. The igloo looks like a hemisphere with radius R. When will the child fall off the slide? Homework Equations See belowThe Attempt at a Solution There are only two forces acting on the child - the force of gravity and the...

Homework Statement A uniform chain of mass 'm' and length 'l' rests on a rough incline (inclination is angle 'Q') with its part hanging vertically. The chain (inclined) starts moving up the incline (and the vertical part moving down) provided the hanging (vertical) part equals to 'n' times...

Homework Statement A 5.0kg block of wood sits on a table with a string running over a pulley suspending a mass. The largest mass that can be suspended without moving the block of wood is 0.75kg. a) Calculate the coefficient of friction in this case. b) What type of coefficient of friction has...

Homework Statement Image below is a sketch of the situation. A pallet is vertically moved towards the conveyor. The purpose is that this stack of pallets (about 15 pallets) gets guided by 2 plate structures so that the stack is ligned out. Homework Equations I'm wondering now what the optimal...

Homework Statement Homework EquationsThe Attempt at a Solution If the two blocks were to move together when the external force of magnitude mg is applied , the acceleration would be mg/3m = g/3 . This acceleration would have to be provided by friction . Value of friction should be mg/3 . But...