Frictional force Definition and 260 Threads

Homework Statement a truck driver loads two identical untethered crates stacked one upon the other. no sliding takes place. make separate sketches to show the forces acting on each crate when the truck is traveled on a horizontal straight road while accelerating. Homework Equations...

I have made some experiment as a part of my research work with special type of mini-pate type plasma actuator. I have varied electrode positioning over the cord length like the attached figure. By varying the gap between upper electrode and trailing edge, I got different induced velocity. I...

Homework Statement A dragster reaches 350km/h from rest to 6.2s. If the car is 800kg and generates a driving force of 14000N, find the force of friction acting on the car. Homework Equations The Attempt at a Solution 350km/h = 97.2m/s a=\frac{97.2m/s - 0}{6.2s} = 15.7m/s^2...

Homework Statement Derive an expression for frictional force acting on a spherical objects of radius R moving with velocity V in a continuous viscous fluid of fluid's viscosity η . Homework Equations please do not use dimension analysis to prove. The Attempt at a Solution

Homework Statement I have a few questions I need help with on my assignment. I cannot wrap my head around this work and energy chapter. Anyway here it is; A 62.7-kg skier coasts up a snow-covered hill that makes an angle of 25.2° with the horizontal. The initial speed of the skier is...

A 40 kg child climbs a 2.5 m vertical ladder to the top of a playground slide. Starting from rest at the top of the ladder, the child slides down the incline, which makes an angle of 22 degrees with the horizontal ground. Friction is present during the descent and the child reaches the bottom of...

a body of 5 kg mass is resting on a board which is gradually tilted until, at an angle of 30 degrees to the horizontal, the body begins to move down the plane. find coefficient of friction and magnitude of the normal and frictional forces when the body begins to slip. i managed to workout...

Homework Statement A crate with a total mass of 50 kg is initially at rest on a level floor. A horizontal force of 150N pushes the crate across the floor at a constant acceleration of 1.2m/s2. What is the magnitude of the frictional force acting on the crate? Homework Equations The...

Homework Statement A 40 kg block slides down arough incline of 35 degrees with a constant velocity. Find the frictional force acting on the block. Homework Equations Fgx = Fg sin theta Fgy = Fg cos theta Fg = mg The Attempt at a Solution Well I drew a diagram and solved for my Fgx...

Homework Statement In an emergency stop on a level, dry concrete road, the magnitude of the friction force when sliding is approx 80% of the weight of the vehicle what is the stopping distance required for a vehicle traveling at 88km/h (24.444m/s). assume that all the wheels lock when the...

Homework Statement Place a book flat on a table and press down on it with your hand. Now suppose the hand-to-book and table-to-book coefficients of kinetic friction are 0.48 and 0.40 respectively. The book's mass is 0.80 kg and your downward push on it is 10.90 N. How much horizontal force is...

In unloading a truck a man allows a 120kg crate to slide down a plank inclined at 30.0o to the horizontal. The crate accelerates at 3.90ms-2. What is the size of the frictional force? I know I need an equation for frictional force on an incline plane to slove this but that's where my problem...

Hi guyz... I am having a problem with this question. Hope to get some guideline from here :D An engine of mass m moves without driving force but under the influence of the frictional force f(v)=(alpha)+(Beta)v2 on horizontal rails. Let the initial velocity be v0. (a) After which time does the...

Homework Statement A skier of mass 57 kg skis down a 10° slope @ constant velocity. The force of air resist. has a magnitude of 74 N. Find the frictional force on the skis. Homework Equations F=ma F(fr) = (mu)(Fn) The Attempt at a Solution I found Fn= ma where is 558N so...

Homework Statement A certain car experiances a limiting maximum frictional force equal to 75% of its weight. What is the smallest radius of bend that it can move around on a level road at 20ms-1Homework Equations F=mv2/r The Attempt at a Solution Couldnt get past last stage.

Homework Statement A car weighing 1.07 104 N is at rest on a 32.5° incline. Each wheel bears an equal part of the car's weight. Thus the axles apply a vertical downward force of 2.68 103 N to the center of each wheel. The tire radius is 35 cm and the brake radius is 20sm (a) Find the...

Homework Statement A uniform ladder 5.1 m long rests against a frictionless, vertical wall with its lower end 3.1 m from the wall. The ladder weighs 165 N. The coefficient of static friction between the foot of the ladder and the ground is 0.39 . A painter weighing 739 N climbs slowly up...

I've been trying to figure out the friction coefficient of some brake pads. My test fixture only allows me to pull (F2) a brake disc between two brake pads clamped around the disc with a force F1. I then measure with a load cell the maximum force required for the brake disc to slip. My...

Homework Statement A certain light truck can go around a flat curve having a radius of 150 m with a maximum speed of 32.0 m/s. With what maximum speed can it go around a curve having a radius of 75.0 m? Homework Equations Fc = m(v^2/r) Fc = net centripetal force m = mass v = tangenital speed r...

Homework Statement A 64.9-kg skier coasts up a snow-covered hill that makes an angle of 23.4 ° with the horizontal. The initial speed of the skier is 8.95 m/s. After coasting a distance of 2.31 m up the slope, the speed of the skier is 4.40 m/s. (a) Find the work done by the kinetic frictional...

Homework Statement A car (m = 1840 kg) is parked on a road that rises 18.7 ° above the horizontal. What are the magnitudes of (a) the normal force and (b) the static frictional force that the ground exerts on the tires? Homework Equations F=ma Fg=mg Ff=uN The Attempt at a Solution...

Homework Statement A ladder 12.0m long weighing 125 N rest against a smooth vertical wall. The bottom of the ladder makes an angel of 67 with the deck. A bucket of paint with a mass of 14kg rests o a rung, 7.00m from the bottom end of the ladder. What is the frictional force exerted on the...

Homework Statement Batman is driving the Batmobile down a hill coming from the Bat Cave. This hill is inclined at an angle of 30 degrees to the horizontal and has a coefficient of kinetic friction of 0.28. What force must the Batmobile's engine apply to cause the Batmobile to accelerate at...

Homework Statement You have a ball rolling down an inclined plane of h height and an angle theta. I have to calculate the frictional force if the ball is not slipping Homework Equations t= FRsin theta I=2/5mR^2 The Attempt at a Solution Where on the ball is the torque being...

Homework Statement A hydraulic brake system is shown. The area of the piston in the master cylinder is 6.35 cm2, and the area of the piston in the brake cylinder is 1.72 cm2. The coefficient of kinetic friction between the brake shoe and the wheel drum is 0.453. How large is the frictional...

Homework Statement We have to do a lab on friction in which there was a pulley with a mass attached to it which is held by another mass on the table and an inclined plane with a mass on it. The question is "Based on your work above, show why μs = m/M". I don't understand how to do this. Also...

A block is at rest on the incline shown in the figure. The coefficients of static and kinetic friction are µs= 0.67 and µk = 0.57, respectively. The acceleration of gravity is 9.8m/s^2 1. -> What is the frictional force action on the 42kg mass? Answer in units of N. N = mg cos x...

Homework Statement Three identical boxes sit on concrete floor, each box weighs 30 lbs (133 N). Each has a coefficient of static friction of 0.74 and a coefficient of dynamic friction of 0.64. Horizontal force of 80 N is applied to Box 1, horizontal force of 100 N is applied to Box 2, and...

Homework Statement A slide similar to der stuka is 35.0 meters high but is a straight slope,inclined at 45.0 degrees with respect to the horizontal. If a 60kg woman has the speed of 20.0m/s at the bottom and the work done by frictional force on the woman is -8.58 x 1000J, find the magnitude...

Homework Statement If m1 = 4.0kg, μs = 0.40, m2 = 2.0kg, θ = 30°, what is the magnitude of the frictional force on m1? Give your answer in Newtons, to one decimal place. Use g = 9.81 m/s2. http://bcs.whfreeman.com/WebPub/Physics/tiplerphysics6e_bridge/question_bank_images/fig5-62.png?2908...

A small girl applies a horizontal force of 2 Newtons to a 10-Newton box which slides across the floor with a constant speed of 3 m/s. What is the frictional force, in Newtons, by the floor on the box? F=ma The correct answer is 2 but I don't understand why. If the horizontal force is...

one of the laws of friction states that the frictional force is independent of the area of contact,and velocity,how true is this? my book says this particular law is only approximately true.

Is frictional force really a force since a force is a push or pull? Does frictional force give a push or a pull if its really a force? Thanks

Homework Statement A 1000 kg boat is traveling at 90 km/h when its engine is shut off. The magnitude of the frictional force fk between the boat and the water is proportional to the speed v of the boat: fk = 70v, where v is in meters per second and fk is in Newtons. Find the time required...

You are driving 2500 Kg car at a constant speed of 14 m/s along an icy, but stright and lvel road. While approaching a traffic light, it turns red. You slam on the brakes. You wheels lock, the tires begin skidding and the car slides to a halt in a distance of 25 m. What is the coefficient of...

Homework Statement A person pushes with force of 220N on a 40 kg create. The coefficent of kinetic friction of 0.35. What is the magnitude of the frictional force? Homework Equations Ff = uN The Attempt at a Solution so do I just go Ff = 0.35*(40kg)(9.81m/s^2)...

Homework Statement "Friction hinders translation but aids rotation" If a uniform disc is placed on a surface and a force is applied tangential to it, why is the direction of friction same as that of the force. This would surely hinder rotation and aid translation, right? Homework...

Hi PF, I have a question. Say a particle describes a circular motion over a table. We have that the modulus of the centripetal force must equal the one of the static friction force, right? And according to Newton's second law the frictional force must be parallel to the radius pointing at...

Homework Statement If a force of 150 newtions is needed for a 600 Newton weight to overcome friction, what is the coefficient of friction? The Attempt at a Solution I'm really confused, I drew a force diagram but it didnt help. I know I need to get the frictional force to solve for the...

Homework Statement Acceleration of a car is -12.2 m/s/s. The car has a mass of 925 kg. Find the frictional force. The Attempt at a Solution So A=-12.2, M=925 kg Fnet=MA =925(-12.2) = -11285 N Fg=mg =925(9.8) =9065 N Since there is no vertical direction...

I am struggling a little bit on this problem. Any help is appreciated. Homework Statement A 5.60 kg block is set into motion up an inclined plane with an initial speed of v0 = 8.10 m/s. The block comes to rest after traveling 3.00 m along the plane, which is inclined at an angle of 30.0° to...

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 coefficients of friction for the block and surface are us = 0.40 and uk = 0.25. Determine the magnitude of the...

Homework Statement http://www.webassign.net/userimages/jlabelle@dartmouth/graph.gif A block with mass m = 10 kg slides along a horizontal floor. The kinetic friction force opposing the motion of the block is constant at a value 14 N. At clock reading t=0.0 s and position x=0.0 m, the block...

Homework Statement A force of 43.0 N accelerates a 5.0-kg block at 6.1 m/s2 along a horizontal surface. How large is the frictional force? What is the coefficient of friction? Homework Equations F = ukFn The Attempt at a Solution Fthrust = Ffriction = ukFn = ukFg = uk x m x g = ? x 5.0 kg x...

frictional force! help! Hi There, I'm having trouble with these physics question in my homework: 1. An object of mass 1.5kg rests on a slope making an angle of 30 degrees, with the horizantal calculate: a) the frictional force and b) the normal reaction acting on the object...

1. A force of 800N parallel to the plane is applied to a 100kg block on the plane to push it up the plane. If the component of the weight down the incline plane is 500 N, what is the frictional force? 2. Frictional force = u.Normal Force 3. Fi = Wx + Ff Ff = Fi - Wx...

Homework Statement A 0.5 kg block is sliding across a table top with an inital velocity of 0.2 m/s. It slides to rest in a distance of 0.7m. Find the average friction force that retracted its motion. m=0.5kg vi=0.2m/s vf=0 d=0.7m ff=? Homework Equations vavg= vf-vi, then d/vavg= t...

The alarm at a fire station rings and a 96.0-kg fireman, starting from rest, slides down a pole to the floor below (a distance of 3.55 m). Just before landing, his speed is 1.79 m/s. What is the magnitude of the kinetic frictional force exerted on the fireman as he slides down the pole...

Hi all i have a question that i couldn't figure out here is the question. 1.A block is at rest on the incline. The coefficients of static and kinetic friction are μs = 0.7 and μk = 0.59, respectively. The acceleration of gravity is 9.8 m/s2 .What is the frictional force acting on the 16 kg...

Homework Statement A 1.6-kg block slides down a plane (inclined at 25° with the horizontal) at a constant speed of 2.0 m/s. At what rate is the frictional force doing work on the block? Homework Equations The Attempt at a Solution I think that you have to find the potential...