Read about friction | 416 Discussions | Page 1

  1. Kaushik

    Find the frictional force acting on a solid cylinder

    This was the answer key provided: My questions are the following: if the force required for rotational equilibrium is more than the limiting static friction, then the body will rotate aka slip over the surface. When it slips, the frictional force will be kinetic and not static, right? If I...
  2. schrodingerwitch

    I Vectorial issue of friction

    Considering an stopped object in a horizontal plane, the frictional force between the object and the plane would be the product of the friction coefficient (static or kinetic if there was movement between the surfaces) by normal. Since the normal in this case would be given by N (vector) = - mg...
  3. J

    Applications of Newton's laws - coefficient of friction

  4. SamRoss

    B Simple forces described in terms of fundamental forces

    My first question is actually, what happens when any two objects get near each other? This question is often phrased as "Why can't you really touch anything?" or "Why can't you walk through walls?" I have heard two answers: 1. the repulsion between electrons 2. the Pauli exclusion principle...
  5. S

    What is the maximum frictional force?

    In the attachment I am supposed to calculate the maximum frictional force of a block on a 35 degree angle incline (that is the point at which the force acting opposite frictional force is highest) I make it out to be sin(35)*120N = 69N but the book says 675N and it gives it as...
  6. goodOrBad

    Feedback on the concepts surrounding pulley, ropes, friction

  7. goodOrBad

    Block on a slope with a weight

    This is my attempt of solving it
  8. goodOrBad

    Help with a two block problem

  9. C

    How far can the person climb up the ladder before it starts sliding?

    Look on picture two for my equations, I’m pretty sure my first three equations are correct as it’s the same on the answer paper I got. Answer paper only shows the three equations and correct answer so I have no idea how they got to it. When I put the equations togheter And solve out ”h” i get...
  10. Hamiltonian299792458

    Two block problems with friction

    the maximum value of friction between the surfaces of the blocks is ##60N## the friction should be self-adjusting until this maximum value. Hence the force of friction in the given scenario should be = 30N but this is physically impossible as if this is the case the top block will be at rest and...
  11. Like Tony Stark

    Direction of the normal force when acting on a tilted object

    My question is: given a rigid body which interacts with a surface, what's the direction of the normal force? Because, as the word says, it has to be normal to the surface. But when treating problems of a vertical rod which is slightly pushed and forms an angle ##\theta## with the surface, some...
  12. Hamiltonian299792458

    Two blocks kept side by side and friction between them

    if the applied force F >(M+m)g/##\mu## the force of friction between the two blocks should become f=N##\mu## and since the normal reaction will be greater than what it should be to keep the block m at rest with respect to M, will the mass m accelerate upwards. in short,for let's say a very...
  13. M

    I How do I read this equation for air friction/drag on an object?

    I am trying to understand an excerpt from an article describing the vibrations of a string (eg. guitar/piano) which reads as follows: This is basically the wave equation with Δm representing a small piece of mass from an interval of the string and two forces added to the right side. He...
  14. ItsukaKitto

    Maximum height a block reaches after separating from a curved moving ramp

    Diagram attached at the end I personally think there's something wrong with this question, and I'd like if someone can tell me whether it's the question that is wrong or my approach. If I attempt the solution thinking that M should be stationary, the solution is simple. 0 - 1/2 mv^2 = -mgh...
  15. Rahulx084

    Some questions about Friction in fluid flow

    I have few conceptual doubts in fluid mechanics. Here is the one I will ask first. I want to understand the force direction acting on the solid liq interface during fluid flow, Lets say a fluid is flowing in a pipe. Now the fluid applies a shear stress at the walls of pipe in the direction of...
  16. rakailee

    Truck with attached inclined plane and a block on the incline

    I tried solving this by assuming the acceleration of the truck and block to be the same so the block would stay on the incline. Also, I would assume truck ma = static friction, block ma = mgsintheta... then I solved for a to plug into 1st equation to get 12990 N. Is this correct? I wasn't sure...
  17. G

    Determining the power of frictional force

    I can say that the frictional force always against the rolling sphere and the velocity is increasing for the ball. So The dot product F.v keeps on getting more and more negative, so how can the Pf remain constant? Well the velocity increases along the incline and the force of gravity is down...
  18. Physics lover

    Value of frictional forces in a 3-block system

    So I started by checking the options.I substituted the value of friction in the equations I got by making free body diagrams.I got different value of Tensions.For 1 and 3 Tension came to be 38 N.For 2 Tension came out to be 42N and for 4 Tension came out to be 40 N. Now I think that I will take...
  19. J

    B What is the orientation of the vector of friction?

    Hi, It is my first message :) I hope you are all fine and safe in these difficult days ! I cannot find the good orientation of the vector of friction. A circle moves in translation to the right and in the same time the wall rotates around A0. A0 is fixed to the ground. There is always the...
  20. SilverSoldier

    Mathematically Modeling a Rolling Body with Slipping

    Basically, I want to know if my assumptions and workings are correct. This is how I see this situation. First, I'm viewing this body as a series of disconnected points, like I have in this animation I made, modeling purely rolling motion. Modeling the body like that worked in that case, and...
  21. K

    Aerodynamics of a Train

    Summary:: How can I measure the friction of a train with its rails and the air. How can I measure the friction of a train with its rails and the air. You can assume that the face of the train is like the picture below. If you need any specifications just let me know
  22. rakailee

    Box on a slanted plank with friction attached to a spring

    I first find the force of friction to be (2)(9.8)cos(65)(.22), then I find the pull of gravity to be (2)(9.8)sin(65). The full equation I set up to be: 0 = kx + force of friction minus the pull of gravity This gives me the wrong answer, 0.44 . My free-body diagram is that kx and force of...
  23. MathDestructor

    Mechanics: Slope Friction Problem

    So far, I have this: For Part ii) I know that: mgh = xmgsin(theta), but I don't know how to go further
  24. Kaushik

    B Friction and surface area

    From what I read on the internet I found that increase in surface area that is in contact is offset by the reduction in pressure. What exactly does it mean? This is what I understood from the it (but my understanding might be absurd :-p): does reduction in pressure mean that the "hills" or...
  25. Helena Durrant

    Problem involving friction, with a mass being pulled up a slope

    (The answer from the markscheme is 26.7)
  26. Thijske

    Kinetic friction coefficient of aluminum on lubricated cast iron

    Hey all, I was recently searching for kinetic friction coefficients, and I noticed that for a reason which is unknown to me, some materials had not been appointed such coefficient. The specific kinetic friction coefficient that I'm looking for is aluminum on greasy/lubricated cast iron. Any type...
  27. T

    AP Physics 1 Help? Centripetal motion/Kinematics/Friction problem

    I think I have solved the first three, and only really need help on question four. For number one, I used Fc = (Mv^2)/R and just rearranged it for velocity so I ended up with v = sqrt(ac * R) For number 2 I used Ff = Fn*mu and got Mg*mu = Ff For number 3 I used w = Ff*d and got w = -Mg*mu*l...
  28. K

    B Resistive force that a nail will have to overcome to penetrate a piece of wood

    lets say a hammer of 0.5kg strikes a nail at 10m/s. The nail penetrates into the wood by 1cm. The reason why the nail stops is because friction has eventually overcome the nails momentum. The retardation of the nail can be worked out, but Can you calculate the force that stops the nail if you...
  29. Prabs3257

    Velocity of an object on an inclined plane

    I used work energy theorem between initial top point and point x along the incline(downwards) i got the expression of v then diffrentiated it to get a maxima but it gives me a wrong ans which is 10/6 but the actual ans is 10/3 please tell me what i did wrong
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