What is Pulley with friction: Definition and 16 Discussions

A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that does not transfer power to a shaft, but is used to guide the cable or exert a force, the supporting shell is called a block, and the pulley may be called a sheave.
A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain.
The earliest evidence of pulleys dates back to Ancient Egypt in the Twelfth Dynasty (1991-1802 BCE) and Mesopotamia in the early 2nd millennium BCE. In Roman Egypt, Hero of Alexandria (c. 10-70 CE) identified the pulley as one of six simple machines used to lift weights. Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another. Plutarch's Parallel Lives recounts a scene where Archimedes proved the effectiveness of compound pulleys and the block-and-tackle system by using one to pull a fully laden ship towards him as if it was gliding through water.

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  1. Memo

    Particle dynamics (mechanics): inclined plane, pulley, two blocks

    (sorry for my poor English) +For m1 to go down, the Net force acting on m1 must be smaller than 0 -> T-m1*g<0 -> T<m1*g(1) _Evaluating object 2 perpendicularly: N-Py2=0 -> N=m2*g*cosa _Evaluating object 2 parallel: -Px-f+T=0 -> T=sina*g*m2 + k*m2*g*cosa (2) _Insert 2 into 1: m1g > sina*g*m2 +...
  2. YehiaMedhat

    Pulley with friction, how to get the friction in the pulley?

    First, I assumed that the tension in the rope connected to the block A equals the static friction ##\sum{}^{} F_x =0 \rightarrow T=N_A*0.5=100N##, then the W weight or force equals to the tension in the pulley and the tension T ##W=100+\frac{2W}{\pi} \rightarrow W=275.2N## It's the first problem...
  3. jschim

    Oscillating Spring in a Frictionless pulley system

    1. Draw Free body Diagram for each weight. 2. Solve for Tension in Rope. 3. Find Spring Constant. 4. Find omega (w, or angular velocity)
  4. EastWindBreaks

    Why is the second approach incorrect? pulley problem

    Homework Statement Homework Equations friction force = F_v m=m1 The Attempt at a Solution is method 1 correct? if so, why method 2 came out with a totally incorrect answer. I understand that you can also set up acceleration equations for m1 and m2, since their acceleration are equal, and...
  5. shubham_ju

    Will a Massless Pulley with Friction Rotate with Unequal Masses on Either Side?

    a massless pulley with friction between its surface and the string passing over it .If string is having two unequal masses connected to it on both side of pulley then will the pulley rotate?
  6. J

    "How Fr=Ialpha Works in a Pulley w/ Mass

    Homework Statement How does Fr=Ialpha work and how is it applied to a pulley with one mass attatched? Homework Equations F * r = I * alpha I = moment of inertia The Attempt at a Solution I'm assuming F would be the tension of the pulley with the string. But how does that equation work? can...
  7. Her0

    Finding the force of kinetic friction without a coefficient

    Homework Statement In a lab assignment we created a Fletcher's trolley system and were asked to calculate the normal force, the force of friction, and then create a graph of both to find the coefficient of kinetic friction. So far, the variables I have are: Hanging mass: 0.100 kg Sliding...
  8. D

    Coefficient of Friction of Fixed Atwood Pulley

    Homework Statement Hi, I was wondering how you would isolate for and calculate the coefficient of friction in an Atwood pulley, with one fixed pulley, with two masses hanging off of it on either side. There is no table or surface that the masses are touching or resting on, they are both...
  9. L

    Pulley problem with 2 masses and an incline

    1. A mass on a flat surface is pulled with an angled force of 200N (as shown) and is connected by a massless rope/pulley to another mass below on an incline. Find the acceleration and Tension in the rope.Homework Equations Fnet = ma Fg = mg Ff = Mu x Fn The Attempt at a Solution Had a question...
  10. T

    Forces; Two blocks connected by a pulley with friction

    Homework Statement A massless rope is attached to Block A, which as mass m_A and rests on a horizontal surface with coefficient of kinetic friction u_k. The rope passes over a frictionless, massless pulley and Block B is attached to the other end. When the blocks are released, Block A moves to...
  11. E

    Searching for any lead on realistic cord mechanics

    Hi all, I'm a physicist, and I'm now trying to understand and model a problem with a multishafted cord, being pulled from one side in order to transfer force. The cord has its own elastic properties (elongation, bending etc.), it goes through several pulleys with friction, and most likely its...
  12. D

    Calculating Time for Mass to Travel Distance on a Pulley

    Homework Statement The two blocks in the figure are connected by a massless rope that passes over a pulley. The pulley is 16cm in diameter and has a mass of 1.3kg. As the pulley turns, friction at the axle exerts a torque of magnitude 0.50 N*m. If the blocks are released from rest, how long...
  13. A

    Normal force of real pulley: Which direction is it?

    Consider a pulley fixed to the ceiling. A mass-less string is wrapped around it, with each side of the string hanging down either side of the pulley. Since the pulley has friction with the string, tension along the string will vary. Let's say the string is attempting to move clockwise, so the...
  14. J

    ANSYS Workbench - 3D rope on a pulley with friction

    Hello everyone, First of all, I want to excuse for my not perfect English since it isn't my mother tongue. However, now to my problem, which I'm facing at the moment. As part of my master thesis I have to simulate the application of a fastening device, which I develope during my master...
  15. A

    Two Blocks and a Pulley with Friction

    Homework Statement Blocks A and B are connected by a cable that passes over support C. Friction between the blocks and the inclined surfaces may be neglected. Knowing that motion of block B up the incline is impending when mB = 4.5 kg, determine: (a) the coefficient of static friction...
  16. S

    Free Body Diagram of Pulley with Friction

    Homework Statement Draw a freebody diagram of the fixed pulley used in your lab. I am trying to get ahead in my statics class so I can start preparing for finals, but we haven't covered this in class yet, and it is not in our textbook. Our lab section is a bit ahead of our lecture...
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