Friction force Definition and 235 Threads

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...

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 A lifting system can be modeled as two blocks of mass m1 and m2 hanging from two pulleys, connected by ropes to a third block of mass M = 100 kg, lying on top of a horizontal surface. There is gravity g = 9.80 m/s2. a) Ignoring at first friction, find an expression for the...

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...

As we all know, for the most part, the kinetic friction force is, for the most part, constant. After moving my cup across my table, this thought crossed my mind. If I move my cup across the table with a constant speed, then the force I'm applying must be equal to the kinetic friction force...

Hi guys, I was wondering if it is possible to have a pure planar rotation of a rectangular-prism shaped rigid body on a planar surface when it is subjected to a planar point force at the tip. Is there any range for the point force such that it can not break the static friction force (so no...

Homework Statement Force is applied to a body from A to B, and then withdrawn. Question: What happens after B ? 1. Will the body keeps accelerating after B ? 2. Will the body keeps moving with constant velocity after B ? Consider both friction and frictionless surface. 2. The attempt at...

Homework Statement A disk roll without slipping down a incline plane. Identify the forces acting on the disk, explain qualitatively which of these forces do work. Homework Equations The rotational work is given by W=\int \tau_z d\theta (1) , where \tau_z is the component of the torque...

Homework Statement A 500 kg ox runs and speeds up by 3 m/s2, but is held back by a 120 kg plow that is attached to its back. Assuming the coefficient of static friction between the horse's hooves and the soil is 0.73, what is the magnitude of the static friction force the soil exerts on the...

Homework Statement A 2000 kg plane is landing at an airfield with an initial speed of 50 m/s. The force of friction is 1/4 the weight of the plane. What is the acceleration of the plane? Homework Equations Fnet = ma Fnet = something - ff The Attempt at a Solution 2000a = thing I don't know...

solved

Homework Statement A box was dragged downward from the state of rest through an inclination 10.0 m at an angle of 25 degree. The speed when the box arrived at the base is 3 m/s. a) what is the coefficient force between the box and the surface? b) how many work is done to move the box downward...

Homework Statement A man is exerting a force of 200 N on a refrigerator and pushing the fridge across a rough floor at a constant velocity to the right. How much friction force acts on the refrigerator ? Give a number and appropriate units. Homework Equations none The Attempt at a Solution I...

Homework Statement The 4000N concrete pipe is being lowered from the truck bed when it is in the position shown: If the coefficient of static friction at the points of support A and B is 0.4, determine where it begins to slip first: at A or B or both at A and B Homework Equations It's not...

Homework Statement At a construction site, a 62.0 kg bucket of concrete hangs from a light (but strong) cable that passes over a light friction-free pulley and is connected to an 80.0 kgbox on a horizontal roof (see the figure (Figure 1) ). The cable pulls horizontally on the box, and a 50.0 kg...

Homework Statement A car moving at 50mph coasts to a stop while traveling a distance of 150ft on level ground. what is the size of the friction force needed to bring this car to rest? Homework Equations vf^2 = vo^2 + 2a(xf-xo) F=ma Fk=un[/B] The Attempt at a Solution I first converted...

Hi, I'm wondering what's going on when a friction force of a surface is applied to a moving block as the block slows down to zero and it, the friction force, is the only horizontal force applied. Does the friction force continue at a constant value until the last moment and just drop to 0N or...

Homework Statement A small box (mass m1) is placed upon a large box (mass m2); the large box i placed on a horizontal table. The boxes begin a rest on the table. The lower box is hit by a horizontal blow at the time t=0 resulting in a initial velocity v0. The frictioncoefficient between all...

Consider a sled being pulled across the snow at a constant velocity. Imagine that a child pulls the sled with a force of 142 N, and that the rope makes an angle of 32 degrees with the horizontal. The sled moves along the snow with a constant velocity. The sled has a weight of 119 N. a)Draw a...

Homework Statement There is a block of 1kg (m1) resting frictionless on another block of 5kg (m2). m1 is connected by a horizontal spring to m2. m2 is resting on an inclined plane of 45°. Between m2 and the plane there is friction. A force of 200N is applied on m2, pushing it upwards. F=200N...

Homework Statement Homework Equations F = ma The Attempt at a Solution When drawing a FBD for block 1, I couldn't figure out if the friction force between the blocks was toward the left or toward the right. Similar situation on block 2. How would I determine this?

A 1.2 kg block is resting on horizontal surface. The coefficient of static friction between block and surface is 0.5. What is the magnitude and direction of force of friction on block when magnitude of external force acting of block in the horizontal direction is 9.8 N fs = μs*N, N = mg m =...

Homework Statement A car goes on a horizontal circular road of radius ##R##, the speed increasing at a constant rate ##\frac{dv}{dt}=a##. The friction coefficient between the road and the tier is ##\mu##. Find the speed at which the car will skid. Homework EquationsThe Attempt at a Solution I...

Homework Statement A child pulls a 10lb sled up a 15 degree incline at a constant speed. The child is pulling on a rope attached to the sled. If the rope is inclined at 37 degrees to the horizontal and there is an 8 pound tension in the rope, what is the coefficient of friction?Homework...

Homework Statement A 60-kg person rides down an icy hill of 20° slope while standing on a 3.0-kg flat-bottomed bathroom scale. Assume there is no frictional force between the bottom of the scale and the hill. The static friction force the scale exerts on the person is Homework EquationsThe...

Homework Statement A 20 kg wagon is released from rest from the top of a 15 m long plane, which is angled at 30° with the horizontal. Assuming there is friction between the ramp and the wagon, how is this frictional force affected if the angle of the incline is increased? Homework Equations...

I'm doing some experiments where I need to calculate the resistance force on a cylindrical body (cable) when it's being pulled through water saturated sand We derived formula from a theory which was originally based on a square body by using stress components. This way we know the pressure at...

I'm using a review book to study for physics but I don't understand how this answer was obtained. I got a different answer. When I googled the exact same question, I found a website that got the same answer as me... so is the book wrong? The question is as follows: 1. Homework Statement A 15...

So I'm having a hard time understanding baked turns involving roads. Mainly I'm confused on how to derive the friction force into the x and y components and why it turns be like so. I also am confused about when i encounter a problem that involves friction in banked turns like in the picture...

The harder I push a book to a wall, the larger is the friction force, since friction is (coefficient of friction (times) the force I use). Why won't the friction force make the object go up instead of stay where it is since the friction worse can get arbitrarily large while gravitational force...

Just a question i was curious about

I have tried this question but I seem not to be getting any where. Qn; An ice-hockey puck is struck from one end of a rink of length 27 m towards the other end. The initial speed is 6m/s, and the puck rebounds from the boundary fence at the other end with a speed which is 0.75 times the speed...

Hello everyone, I cannot understand the logic behind determining the directions in the rolling problems. In all examples I have seen has a logic. Let us assume a rolling cylinder is moving to right as accelerating. If the cause of the acceleration is a torque the direction of the friction force...

Homework Statement If a 2.5 kg rubber ball is rolled across the dry concrete floor with an acceleration of 4.0 m/s^2[E]. Determine the friction force required to stop the ball. (Drawing a free body diagram will help illustrate this situation) Homework Equations Fk= µk(Fn) F=maThe Attempt at a...

Please help! I have a test tomorrow. 1. Homework Statement A car with a weight of 15,000 N moves horizontally at 30 m/s. a) What is the car's KE? b) What will be the magnitude friction force to stop the car over a 60m distance? Homework Equations F=ma KE=1/2*m*v2 The Attempt at a Solution a)...

Homework Statement A person pulls a box (m=10 kg) horizontally with +2m/s2 acceleration by applying 45 N force. The displacement of the box is 8 meters from initial position. a) How much work is done by applied force? b) How much work is done by kinetic frictional force? Homework Equations Wf...

Homework Statement Mass of the bus is 20 tons. It accelerates to 10 m/s (from initial speed of 0) in 50 meters. Find the coefficient of friction (u) if the force, that pushes the bus = 14*10^3 N m=20t=20000kg S=50m v=10m/s F=14kN=14000N The Attempt at a Solution So we can find out what the...

I have a problem need to be solved here. Someone told me that the friction force must always have the friction coefficient. Is it right or wrong? and we can not calculate the friction force without friction coefficient because this force is only calculated by the coefficient and the Normal...

Homework Statement One surface moves over the other stationary surface. a. Is friction felt by both the surfaces? b. Is the friction force same in magnitude? c. What are the direction of friction forces felt by them? Homework Equations The Attempt at a Solution Since both...

Could some please help me with this problem? Boards X and Y are both massless and 4 m in length. A 4 N force is applied to board Y as shown. Board X is held stationary. The two boards are nailed together at 1 m from the left end of board Y. If the boards do not move, what is the static...

I have a concept about rolling friction which someone might be able to confirm for me. Let's say there is a steel ball rolling on a steel surface. It seems to me that the rolling friction force would be proportional to the rolling object's velocity. My understanding is rolling friction is...

Which of the following statements are true?? OPTIONS: A)a rotating ball is kept on a rough inclined plane.It may remain at rest till it is rotating. B)A rigid body rolls up an inclined plane without sliding. The friction force on it will be upwards. C)A rigid body rolls down an...

Homework Statement What is the greatest acceleration that can be generated by a runner if the coefficient of static friction between shoes and road is 0.95? Homework Equations Fnet = ma Force of static friction: usN Weight= mg The Attempt at a Solution FBD: Positive x-axis is...

Homework Statement A 3 kg block is on a plane inclined at 30.0° with respect to horizontal.Coefficient of static friction Csfbetween block and plane is 0.60. What is normal force , and is the block moving ?? Homework Equations Using second low of Newton (vectors): Fg +f+N=ma. So...

Homework Statement A solid cylinder is dragged over a surface by a constant force F that has an angle θ with horizontal. It rolls without friction around its symmetrical axis. The mass is M and radius is R and moment of inertia is I=\frac{1}{2}MR^2 The cylinder rolls on the surface without...

I have a question regarding a friction experiment, so here's what I have so far: Homework Statement Calculate the approximate force of friction between the wheels of a cart and a ramp it is rolling on by only using the cart's mass and different values of acceleration up and down the ramp...

Homework Statement A barrel of fun consists of a large vertical cylinder that spins about the vertical axis. When it spins fast enough, any person inside will be held up against the wall. http://i.snag.gy/Wh1B9.jpg Question: If you double the angular speed (i.e., \omega _2=2\cdot \omega _1)...

Homework Statement You testify as an "expert witness" in a case involving an accident in which car A slid into the rear of car B, which was stopped at a red light along a road headed down a hill. You find that the slope of the hill is θ = 12.0°, that the cars were separated by distance d =...

Hello! I'm excited to join this physics community and appreciate any help that the people posting in this thread will give me! The problem is this You are lowering two boxes, one on top of the other, down the ramp with length 4.75m and height 2.5m (The ramp has its highest point at the right...

Ap physics friction force please help! Homework Statement A 1000kg car traveling at a speed of 40m/s skids to a halt on wet concrete where the friction force is 6000N. How far does the car slide before coming to a stop? Homework Equations F=mv^2 / r 1000 kg x (40 m/s^2) / r = 6000...