Pulley Definition and 1000 Threads

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. C

    Final lifting weight on a static pulley system?

    Dear Advisor, I tried to read books and searched all around before posting new topic here... I'm carying out testing a hoisting winch at load 400 kN through a system as in picture. My problem is that due to fiber rope i only can measure exactly wire tension by a load cell installed through...
  2. F

    How do I calculate mass of pulley and force of friction on AtwoodMach.

    Homework Statement Basically, I need to calculate the mass of the pulley and friction using data that I collected. Homework Equations I was given: (m1 - m2)g = (m1 + m2 + mp)a + f The Attempt at a Solution For the first part, I collected data using a sensor to find the...
  3. R

    Understanding Velocity in a Massless, Frictionless Pulley System

    Homework Statement Find V if the pulley is massless, friction less and Can take any no of variables but V is be in terms of VP.Ignore gravity and other forces 2. The attempt at a solution If Pulley comes down by X, the length of string towards left(the side not fixed) will increase by...
  4. 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...
  5. U

    Thermodynamics problem, with a pulley

    Homework Statement The diagram is attached. The description of the setup is in the second attachment. I do have solutions to the problem, but I don't understand parts of it. Questions: a) What is the initial pressure in the liquid? b) Please show that the magnitude of the tension in...
  6. J

    Why Does Pulley Require Less Work to Lift Mass?

    As I understand it, pulleys will reduce the force needed to lift objects but require a greater distance. As the number of pulleys increase, the force decreases. But for all cases of pulleys, the work required to lift a given object to a given height will always remain the same. When I attach...
  7. B

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    A pulley 150 mm diameter is driven directly by an electric motor at 250 revs min–1. A V-belt is used to transmit power from this pulley to a second pulley 400 mm diameter against a load of 200 Nm. The distance between the centre of the pulleys is 600 mm, the included angle of the pulley groove =...
  8. H

    Rotational Dynamics: Pulley and mass system

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  9. Ascendant78

    Work-Energy involving two forces on a pulley.

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  10. J

    Can someone explain this please? Weird pulley with Tension

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  11. P

    Calculating Tension and Acceleration in a Pulley System with Applied Force

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  12. J

    Consequences of an Oversized Pulley Bore Hole in Conveyor Systems

    What would happen if the bore hole of a pulley in a conveyor was significantly larger than the shaft like in the figure below: I would imagine if the RPM was high, the whole system would shake violently. However, what if the RPM was around 30 RPM. Would the conveyor still function properly...
  13. E

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  14. A

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  15. Avi Nandi

    How Do You Relate the Accelerations in a Disk and Pulley System?

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  16. T

    Angular Speed of Pulley (Spring, Pulley, Ramp)

    Homework Statement ---Find Angular Speed--- Homework Equations I = 1/2 mR^2 Ug = mgdsinθ Us = 1/2 kd^2 KE = 1/2 I w^2 The Attempt at a Solution Moment of inertia of reel = 1/2mR2 Kinetic energy of the reel = 1/2 mv2 = 1/2(1/2mR2) w2 KE = mgdsinθ (potential due to gravity) +...
  17. A

    Two masses on inclined plane with frictionless pulley

    Homework Statement A 1.00-kg aluminum block and a 4.00-kg copper block are connected by a light string over a frictionless pulley. The two blocks are allowed to move on a fixed steel block wedge (of angle 31.0°). The aluminum block is on the left side, on a flat plane. On the right is the...
  18. Saitama

    Simple problem involving pulley with mass

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  19. C

    A unique rope and pulley problem

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  20. F

    Pulley Problem: Speed after falling a known distance

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  21. D

    How Do You Calculate Movement After Cutting a String in a Pulley System?

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  22. J

    How can I solve a dynamics problem involving a pulley, rod, and rotating masses?

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  23. S

    Two blocks and a mass- and frictionless pulley

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  24. F

    Quick question on Pulley Force Problems

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  25. P

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  26. M

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  27. H

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  28. M

    Understanding Angular Acceleration and Velocity in Pulley Systems

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  29. P

    Can anybody check if I solved this correctly?(tension forces + pulley)

    Homework Statement The pulley can rotate and has no friction. Block m_2 is twice as big as m_1 Find the tensions, T_1, T_2, T_3 Homework Equations Newton's second lawThe Attempt at a Solution Tension 1: By creating a free body diagram only for the block, I got with Newton's second law...
  30. O

    How to Calculate the Mass of the Left Block in a Pulley System?

    Homework Statement The figure shows a 100 kg block being released from rest from a height of 1.0 m. It then takes 0.90 s to reach the floor. What is the mass of the block on the left? Illustration shows a pulley connected to the ceiling, with a block of 100 kg on the right, and a...
  31. P

    Finding the tension in a pulley that rotates

    Homework Statement m_2>m_1 The pulley rotates. Find the tensions, T_1, T_2, T_3 Homework Equations Newton's laws The Attempt at a Solution I know how to solve the problem if the pulley doesn't rotate because the systems would be in equilibrium (Newton's first law) and dividing...
  32. N

    Mass on Pulley problem need to find angular acceleration

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  33. E

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    Homework Statement http://puu.sh/4PDPV.png Homework Equations τ = I*α τ = r*F The Attempt at a Solution EDIT2: Nevermind, manipulated the torque equations wrong, got it now EDIT: Tried again and ended up with an actual answer, but still got it wrong :/ This is the FBD I used...
  34. A

    Spring - Pulley - Mass system. Proving omega is a certain value

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  35. C

    What is the correct acceleration for the inclined pulley problem?

    Homework Statement m1 has a mass of 47 kg and m2 has a mass of 35 kg. the coefficient of friction between m1 and the surface of the inclined plane are us=.42 and uk=.19 m1 is on an inclined plane angled 25 degrees A) if the masses are held in place and then released, will they start to move...
  36. C

    Pulley and Friction: Solving for Mass and Acceleration on an Inclined Plane

    Homework Statement m1 has a mass of 47 kg and m2 has a mass of 35 kg. the coefficient of friction between m1 and the surface of the inclined plane are us=.42 and uk=.19 m1 is on an inclined plane angled 25 degrees A) if the masses are held in place and then released, will they start to move...
  37. P

    Pulley and Circular Motion: Exploring the Mechanics of Rotation

    Delete this post
  38. karush

    MHB Calculating Angular and Linear Speeds of Pulley and Belt

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  39. A

    Blockk on a table with a pulley

    A 8.10-kg hanging object is connected by a light, inextensible cord over a light, frictionless pulley to a 5.00-kg block that is sliding on a flat table. Taking the coefficient of kinetic friction as 0.190, find the tension in the string. I don't know if my equations are right or where to go...
  40. Y

    How Does the Formula for Acceleration in a Pulley System Work?

    Homework Statement A 230-g air track glider is connected to a string hanging over a frictionless pulley. A 100-g mass hangs from the other end of the string. a) Draw force diagrams for the glider and the hanging mass. b) Find the acceleration of each. Homework Equations F=ma...
  41. C

    Solve Mobile Pulley System: Acceleration of 3 Masses

    Homework Statement A light smooth pulley is attached to a support a fixed height above the ground. An inextensible string passes over the pulley and carries a mass 4m on one side. The other end of the string supports a similar mobile pulley; over this passes a second string, carrying masses of...
  42. B

    Calculating Tension in Frictionless and Massless Pulley Systems

    Give the correct tension, T, in the marked rope for each situation. The rope is held so the system is stationary. All ropes and pulleys are massless and frictionless. Follow link for a picture of the pulley systems: http://i.imgur.com/2eBZpC3.jpg A) T = W B) T = W/2 C) T = W/3 D)...
  43. X

    Tension in pulley systems Concept help

    I need help understanding why in problems tension is modeled as T-mg = ma. I understand there are different variations, but the main concept is what I need help with. For example: If i have 2 masses hanging off a pulley (m1=5kg & m2=10kg) then m1 has a downward force of 49N down. The...
  44. E

    Acceleration of two blocks connected by a pulley

    http://puu.sh/4DtNc.png I solved this question, but I don't understand why this worked. I feel like for the final line in my solution it should just be divided by M1, not the combined mass of both blocks. Isn't this synonymous with just M1 being pulled up the ramp by a guy at the top...
  45. C

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    Homework Statement There's a picture with the problem attached A block with mass m = 1.5 kg hangs to the right of two blocks with masses m2 = 2.2 kg and m1 = 1.2 kg which sit on a table. All three blocks are connected with a string and pulley. Neglecting the mass of the pulley, string and any...
  46. C

    Pulley system on an inclined plane with friction.

    Homework Statement Two blocks are connected by a thin inextensible string over a frictionless massless pulley as shown on the picture below The acceleration of gravity is 9.8 m/s2 Given that the two blocks move at 1.9 m/s under an acceleration of 4.1 m/s2, calculate the coefficient µk...
  47. mathmaniac1

    MHB Strings & Pulleys: Equilibrium, Find T1 & Explain

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  48. L

    Transfering power to a pulley attached to a rod

    A picture speaks a thousand words. In this video, at 41 seconds: [URL="http://www.youtube.com/watch?v=FBZWZfbxeJw"] Eugene R transfers power to a pulley attached to a rod but only the pulley spins. I am in the process of fabricating a pulley system like this. My question is: How is this done?
  49. T

    Pulley and cords tension physics

    The pulley in (Figure 1) is suspended by a cord C. Suppose that m1 = 1.0kg and m2 = 3.9kg . Determine the tension in the cord that supports the pulley C after the masses are released and before one hits the ground. Ignore the mass of the pulley and cords. I'm having trouble getting started...
  50. D

    Solve 2-Mass Pulley System Homework for Moving Blocks

    Homework Statement A massless string, passing over the frictionless pulley, connects the two masses as shown. Block m1 hangs vertically without touching the wall, but m2 slides along the wall with friction (μs = 0.61, and μk = 0.14). If θ = 53°, how many times heavier than block 1 must block...
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