Static friction Definition and 507 Threads

Homework Statement Two objects are made of identical material and are tied together with string. The first object has a mass of 5.0kg and the second object has a mass of 3.0kg. Students measure the maximum force of static friction as 31.4N to move both objects across a horizontal surface. a)...

1. A 1760 N force pulls a 266 lg load up a 17 degree incline. What is the coefficient of static friction between the load and the incline? 2. Coefficient of station friction = Force(Static)Max / Normal(supporting) force The Attempt at a Solution

Homework Statement I have a box on a horizontal plane. Given data: mass = 0.25kg height of object = 14 cm width of object = 9cm Calculate the coefficient of static friction. Homework Equations μs = Ff/N (N is the normalforce) F = Ff = μ*N mg = 2.45 Newton The Attempt at a...

Homework Statement My textbook has a true or false problem that says Static Friction can never do work on an Object and they say that it's false.. How can static friction do work?

Suppose a block of mass 5 kg is resting on a horizontal surface and coefficient of static friction between block and surface is 0.2. If the block is pushed against a vertical wall with a force of 200 N, will the static friction oppose the force? The body has no intention of moving as it is...

Are there any fans of truck or tractor pulls out there? I am trying to understand what is happening to the coefficient of friction as the sled transitions from kinetic friction back to static friction. It is a fairly complicated model... The weight imposed on the front plate of the drag...

Why is (Kinetic friction)= fk≤fs (Static friction) ? I understood the "equal to" case but how is the "less than" case possible? Similarly is this related to why is μk≤ μs ?

Homework Statement I´ll show the problem with a picture: Homework Equations M=rxf Sum Forces = 0 Sum Moments= 0 The Attempt at a Solution I recognize that I am completely lost with this problem, so I´ll try to analyze every force acting on every body to show where are my doubts. When...

A chuck is sliding downward an inclined plane with friction. The inclined plane has an angel 26 degrees with the horisontal. At a point the chuck has a velocity 4 m/s. The velocity after 2 seconds goes down to 2 m/s. The g is applied to 9.81 m/s^2. So from here I need to find the kinetic and...

Homework Statement Two people start running from rest. The first person has a mass of 59 kg and is wearing dress shoes with a coefficient of static friction of 0.52. The other person is wearing running shoes with a coefficient of static friction of 0.66. Explain why we do not really need...

a child (m=30kg) sits 5m from the axis of rotation on a flat turn table which makes a full rotation every 8 seconds. A. find the childs period (t) and frequency (f) Full rotation every 8 seconds, T=8 Frequency = inverse of period = 1/8 B. What is the tangential velocity of the child? Vtan=ωR...

Homework Statement A crate (35 kg) is located in the middle of the flat bed of a pickup truck as the truck rounds an unbanked curve in the road. The curve may be regarded as an arc of a circle of radius 80.0 m. If the coefficient of static friction between crate and truck is 0.410, how fast...

Homework Statement A crate has a mass of 42.0 kg. The coefficient of static friction between the surface and the crate is 0.422. The coefficient of kinetic friction between the surface and the crate is 0.3.44. If a person pushes the crate by pushing down at an angle of 24°, what is the...

Homework Statement A 1.2 g pebble is stuck in a tread of a 0.76 m diameter automobile tire, held in place by static friction that can be at most 3.6 N. The car starts from rest and gradually accelerates on a straight road. How fast is the car moving when the pebble flies out of the tire tread...

Homework Statement http://postimage.org/image/530mgjivr/ How come the solution states: (20)(9.8)(0.7cos30 - sin 30) isn't sin30 going in the positive direction? shouldn't the solution be Sin30 - .7cos30? Also, when solving these types of problems should I leave the mg part outside of the...

Homework Statement The coefficient of static friction between a rope and the table on which it rests is μ. Find the fraction of the rope that can hang over the edge of the table before it begins to slip. Express your answer in terms of μ. Homework Equations The Attempt at a...

Circular Motion and Static Friction Problem.. "The Wall of Death" ride Homework Statement A fairground ride called "The Wall of Death" consists of a cylindrical container of internal diameter 6.50m, mounted on a cylindrical axis. The passengers feel as if they are being pushed against the...

Homework Statement There are 2 questions in the attachments both with the same scenario I'm having troubles with. Homework Equations f=ma The Attempt at a Solution I tried finding the budging force between the 2 masses and that was about 4. I don't know where to go from there to...

Homework Statement A dump truck loaded with rock has a coefficient of static friction of 0.4, and a coefficient of kinetic friction of 0.2 between the rock and steel tray. If the truck tilts its bed to 25°, calculate the coefficient of static friction on the load. Hence calculate the angle...

1. A bug crawls outward from the center of a compact disc spinning at 230 revolutions per minute. The coefficient of static friction between the bug's sticky feet and the disc surface is 1.2. How far does the bug get from the center before slipping? Homework Equations fs ≤ μs nThe Attempt at a...

Homework Statement The coefficient of static friction between the box (6.75 kg) and the ramp (30 degree incline) is 0.500. What is the magnitude of the minimum force, F, that must be applied to the box perpendicularly to the ramp to prevent the box from sliding? Homework Equations...

Hello everyone I am a newbie as well as in physics. I am having a problem in a question as in the attachment. I have learned that the equation of the static friction (Fs) of an object is equals to the product of the coefficient to the normal force of the object. In this question, let mass of...

Homework Statement So a hot wheel was put on a linear track, and one end of the track is slowly lifted until the cart starts to move. The height of the one end is measured as 6.45cm and distance (or hypotenuse) is 189.5cm mass of hot wheel is 45.7 g Homework Equations PE = mgh KE =...

Homework Statement I am trying to start a project. My first step is to figure out the time a car fell off of a cliff. I know the height of the cliff which 40 meters, the base of the cliff from the car when it reaches the bottom which is 30 meters. The car has a static friction coeffiecient of...

Hi all, I'm in an algebra based physics class so I apologize if the way I approach the problem is different from what you might be used to. A buddy of mine is calc based physics always gets confused about how I set the problems up. Also, this is my first post! Thanks in advance for the help...

A flatbed truck and Static Friction and Crate "breaking loose" Homework Statement A flatbed truck is going downhill on a slope of 10 degrees at a constant speed of 20 m/s (a little over 50mph). A crate of 500 kg is sitting on the flatbed , without being attached by ropes or cables. The...

Kinetic and Static Friction Problems Please Help! Mr. Bob slid a 250g plate 1.35m across the dish return counter. It slowed with a constant acceleration for 0.85s before coming to a stop. a) Find the magnitude of the force of friction b) What is the coefficient of kinetic friction...

Homework Statement In order to hold a book of mass m stationary against a wall, you must push horizontally with a force of at least P. a. make a force diagram and find the coefficient of static friction b. calculate the coefficient of static friction for the wall and book when at least a...

Homework Statement A small crane is lifting a 10kg box of nails. If the coefficient of static friction is .4, calculate the angle at which the box begins to slide. Homework Equations Fg x component: mg sin Ff = ukmgcos The Attempt at a Solution Fnet = Fgx - Ff Would the net force...

Homework Statement I know that static friction is normally almost always more than kinetic friction. But I do not know how to prove that. I have to find formulas to find static and kinetic friction, but when the object is at rest or constant velocity, F-µ(Fn)=0. It is the same equation for...

Homework Statement The problem is While trying to decide where to hang a framed picture, you press it against the wall to keep it from falling. The picture weighs 5.0 N and you press against the frame with a force of 6.0 N at an angle of 40ºfrom the vertical. What is the coefficient...

Homework Statement A very strong 100kg man is having a tug of war with a 1500 kg elephant. The coefficient of static friction for both on the ground is 1.0. a) Find the force needed to move the elephant. b) What would happen if the man could actually exert such a force? Homework Equations Ff =...

How do you use the angle of uniform slip to calculate the coefficient of static friction? Is there an equation for this? I cannot find it in the module on friction provided with the course... thanks! I found somewhere that tanθ=μk, but that doesn't really help me, as i am looking for μs...

Homework Statement A father gives his daughter a ride on a sled by applying a force F at an angle θ = 26.0° with respect to the horizontal. If the coefficient of static friction is µs = 0.153, and the combined mass of sled and child is m = 24.0 kg What is the minimum amount of force...

Homework Statement A crate, mass = 275 kg, sits at rest on a surface that is inclined at 20.0° above the horizontal. A horizontal force (parallel to the ground), F = 583 N is required to just start the crate moving down the incline. 2. The attempt at a solution U = (((mg sin (∅)) +...

Homework Statement A crate, M = 277 kg, sits at rest on a surface that is inclined at 20.0° above the horizontal. A horizontal force (parallel to the ground), F1 = 594 N is required to just start the crate moving down the incline. To the nearest thousandth, what is the coefficient of static...

Homework Statement A crate of weight Fg is pushed by a force P on a horizontal floor. (a) If the coefficient of static friction is μ s and P is directed at angle θ below the horizontal, show that the minimum value of P that will move the crate is given by P = usFgSecθ / (1 - usTanθ)...

Ok so I already know how to solve it by looking at an example my teacher did in class... This is what I did... 4. A 2.00 kg block is held in equilibrium on an incline of angle θ = 70° by a horizontal force vector F applied in the direction shown in the figure below. If the coefficient of static...

The Known: Mass=2000kg Velocity=50m/s Radius=1000m With the given information the lab worksheet I'm working on is asking me to deduce the coefficient of friction so that I can manipulate the data and answer some questions. The problem I have is that I am not entirely sure that this could...

Homework Statement A 1980kg car starts from rest at point A on a 5° incline and coasts through a distance of 158m to point B. The brakes are then applied, causing the car to come to a stop at point C, 21m from point B. Knowing that slipping is impending during the braking period and neglecting...

Given a circle with a point mass attached, what is the relationship between the linear force and the force of static friction as it rolls without slipping? Each force diagram I made (http://imgur.com/a/xK8i1) seems a plausible place to start: a makes no torque, b makes no linear force, c makes...

Homework Statement Below are six crates at rest on level surfaces. The crates have different masses and the frictional coefficients [given as (μs, μk) ] between the crates and the surfaces differ. The same external force is applied to each crate, but none of the crates move. Rank the crates on...

1. The homogeneous square body is positioned as shown. If the coefficient of static friction at B is 0.40, determine the critical value of the angle theta below which slipping will occur. Neglect friction at A. The image: 2. NA is the Normal force at A, which is perpindicular to the...

Homework Statement A crane is raising a plank carrying two boxes that only differ in weight. The boxes weigh 10kg and 20kg respectively. As the plank tilts toward the heavier box, predict which box will start to slide first. Explain your prediction. Homework Equations Coefficient of...

Homework Statement A child pulls a string attached to a block of mass m = 1.5 kg at an angle θ = 35.5° with an increasing amount of force. When she pulls with a force F = 7.39 N the block just begins to move. What is the coefficient of static friction between the block and floor...

Homework Statement Two blocks of equal mass are connected by a rope of negligible mass that is passed over a frictionless pulley as shown in the figure. The angle made by the horizontal plance and the ramp is 30 degrees. a) If the system is in this configuration and neither block moves what...

Homework Statement Homework Equations See my work.The Attempt at a Solution

A block is sliding down a 30° incline at 1.2ms^-2 Find the coefficient of static friction. [g=9.8ms^2] I am stumped.. Some relevant equations: Fr = μ(Fn) Fn = mg Ultimately I got μ=0.5 ---> This was through mashing and playing with some trig.

Homework Statement a bus passanger has her laptop sitting on the seat next to her while the bus moves at 10m/s, the bus goes around a turn with a radius of 25m. what is the coefficient of static friction in order to keep the laptop from sliding? Homework Equations The Attempt at...

I'm looking over my notes here, we have a rolling disk down an incline plane and my goal is to find its acceleration in terms of its moment of inertia My dilemma is, when finding the torque, I look at all 3 of the forces influencing it (normal, gravity, and the f_s). The n goes through the...