What is Pulley system: Definition and 352 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. minimario

    Analyzing a Pulley System: Solving for Energy and Work

    Homework Statement Homework Equations ## W_{nc} = \Delta KE + \Delta PE ## ## PE = mgh ## ## KE = \frac{1}{2} mv^2 ## The Attempt at a Solution For Block B, ## \Delta KE + \Delta PE = \frac{1}{2} 100 v^2 + (-20)(g)(100) ## For Block A, ## \Delta KE + \Delta PE = \frac{1}{2} 50 v^2 + (20...
  2. A

    Find the acceleration of a pulley system

    Homework Statement Find the acceleration of the system shown on the image, given m1=0.1kg and m2=0.3kg. Mass of pulleys is to be disregarded, and rope is non-stretchable. Homework Equations m1*a=m1*g-T The Attempt at a Solution I am unsure of how the forces of the second body would act and...
  3. H

    Calculating Mass in Box 3 of a Pulley System

    Question Summarized: The box in the middle is remains motionless; how much mass was placed in box 3? box 1: 35kg middle box: 95 kg box 3: ? kg Attempt at the problem:
  4. H

    Acceleration in a Multiple Pulley System

    So if you have two masses connected by a massless string in a multiple pulley system as shown below, the acceleration will be different right? I ask because when doing normal pulley problems where two masses are connected by a single thread, you assume the acceleration is equal, though the net...
  5. NATURE.M

    Unraveling a Complex Pulley System: Finding Accelerations of Two Attached Masses

    Homework Statement Note this problem is from Morin 3.28. The atwood machine has two masses, m. The axle of the bottom pulley has two string ends attached to it, as shown. Find the accelerations of the masses. A small diagram is attached below. Note, at the two loose ends of string, there is...
  6. END

    Mechanics: Acceleration in Pulley System

    1. The problem A 3.0-kg block sits on top of a 5.0-kg block which is on a horizontal surface. The 5.0-kg block is pulled to the right with a force ##\overrightarrow{F}## shown in the figure. The coefficient of static friction between all surfaces is 0.65 and the kinetic coefficient is 0.37. If...
  7. matineesuxxx

    Work-Energy Principle: Pulley System

    Homework Statement (see attatchment) We know masses M and m, and I am trying to describe the downward speed of m in terms of the hight from the ground. There is no friction Homework Equations \sum \text{F} = ma W_{\text{total}} = \Delta K = \int \text{F} \cdot d\text{s} The Attempt at...
  8. T

    What is the Tension in Block m2's String in a Pulley System?

    Homework Statement The diagram shows a system of two blocks suspended by ideal strings and pulleys. If the tension of the string attached to block m1 is T, what is the tension of the string attached to block m2?Homework Equations Due to conservation of string, a1/2 = a2 Force balance on mass...
  9. G

    How Is Acceleration Calculated in a Basic Table Pulley System?

    Homework Statement Mass m1 = 14.9 kg is on a horizontal surface. Mass m2 = 7.48 kg hangs freely on a rope which is attached to the first mass. The coefficient of static friction between m1 and the horizontal surface is μs = 0.571, while the coefficient of kinetic friction is μk = 0.105. If the...
  10. RaikkoBoy7

    Solve Step Pulley System Homework: Acceleration Relation

    Homework Statement A step Pulley system is shown in the figure.The string and Pulley are of Negligible Mass.The relation Between the acceleration of Block and Block will be what then ?I am having troubles in approaching this question! Homework Equations The Attempt at a Solution
  11. C

    The Lagrangian of a Pulley System

    Homework Statement A uniform flexible chain of mass M and length L is hung under gravity over a frictionless pulley of radius a and moment of inertia I whose axle is at a fixed height above the ground. Write down the Lagrangian of this system in terms of a generalized coordinate l denoting the...
  12. D

    Mass and pulley system question

    Homework Statement A mass M = 53 g hangs from a light, inextensible string. It passes without sliding over a pulley. The pulley can be treated as a solid homogeneous disc with mass mp = 12 g and radius 3.6 cm, that turns without friction on its axis. The other end is attached to a mass m =...
  13. N

    Equal tension on rope in a pulley system?

    Suppose the rope involved in the pulley is massless and experience no friction. Why is the force on the right hand side equal to the tension experienced by the rope on the left hand side?
  14. M

    Acceleration on a pulley system with 3 blocks

    Homework Statement Three objects are connected on an inclined table. The objects have masses 8.0 kg, 4.0 kg and 2.0 kg as shown, and the pulleys are frictionless. The tabletop is rough, with a coefficient of kinetic friction of 0.47, and makes an angle of 20.0° with the horizontal. The 8.0kg...
  15. A

    A pulley system with two objects stacked on each other

    Homework Statement Block B, with mass 5.00kg, rests on block A, with mass 8.00kg , which in turn is on a horizontal tabletop. There is no friction between block A and the tabletop, but the coefficient of static friction between block A and block B is 0.750. A light string attached to block A...
  16. F

    Find Mass of Object 2 in Two-Mass Pulley System

    Homework Statement Two masses are attached by a light string and looped over two frictionless pulleys. Object 1 (200g) accelerates upwards at a rate of 4.90 m/s squared. Determine mass of object 2. Homework EquationsThe Attempt at a Solution I tries doing this but don't think its right...
  17. Rugile

    What is the solution for the Pulley System Problem?

    Homework Statement No friction, pulleys and also string are weightless, the tension through the string is distributed uniformly. Find the acceleration of the mass 3M (see image attached) Homework Equations II law of Newton The Attempt at a Solution Well I wrote such equations for...
  18. 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...
  19. P

    Figuring Out Forces in a Pulley System: What and Why?

    Homework Statement I don't really understand how to determine the forces in a pulley system. Like in this picture : http://postimg.org/image/4vxrf59ar/ How do you decide what forces are present for the pulley? Why isn't there a 375lb on the right side as well? What would be the pulley forces...
  20. M

    2 pulley system with three masses. Find the two outside masses.

    Okay, so I did a lab where we had a 2 pulley system that involved a string and three masses. The string is set up so it is in the shape of an m when put on the pulleys. The known mass is put on the middle string (m3) hanging down and the two outside masses (m1) and (m2) are unknown and are not...
  21. 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...
  22. 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...
  23. 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...
  24. 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...
  25. H

    Problem related to pulley system and velocity

    Homework Statement In the given figure if the masses A and B move down with a velocity 'v' at any moment then what will be the velocity with which mass W rises. A purely logical answer would be appreciated and please don't use calculus based approach, as I don't know calculus. Also...
  26. P

    Tension and Force in pulley system

    Homework Statement Due to settlement of soil, a recently planted tree has started to lean. To straighten it, the cable system shown is used, where a turnbuckle on cable AB is periodically tightened to keep the cable taut as the tree gradually straightens. If the force in cable AB is 395 N...
  27. M

    Pulley system with one mass and apparently independent forces?

    So at my gym, there's a cable machine that works like this: You pull on one cable and you lift x mass using y force. You pull the other and find the same thing. If, however, you pull on both, you're still only lifting x mass (you can see the weights) yet somehow each cable is still requiring y...
  28. R

    Finding mass in a pulley system

    1. A simple Atwood’s machine uses a massless pulley and two masses m1 and m2. Starting from rest, the speed of the two masses is 2.2 m/s at the end of 2.9 s. At that time, the kinetic energy of the system is 85 J and each mass has moved a distance of 3.19 m (a) Find the value of heavier...
  29. A

    Pendulum connected to pulley system

    Imagine a standard pendulum. I understand how to work the physics on one but what if you attached that pendulum to a pulley at the top and could apply tension through the line? Let's say you released it at 45 degrees then some degrees later you applied some amount of tension through the pulley...
  30. E

    Acceleration of Pulley system

    An 11KG weight and 33KG weight are suspended by a rope on a pulley. There is an air-resistance force of 77N working on all objects. Determine the acceleration. Fg=mg Fnet=ma ma=f1on2+f2on1 The force of gravity on the 11KG weight is 107.8N (11*9.8) and since this weight will be...
  31. F

    Different tensions in a pulley system and acceleration

    Homework Statement Here is the picture: http://www.webassign.net/giocp1/8-p-058.gif I am to find Tension 1 ( that between crate one and the pulley) and tension 2 (that between crate two and the pulley). The mass of the pulley is MP. Homework Equations See below The Attempt...
  32. N

    Rotational motion on pulley system

    Homework Statement A string passing over a pulley has a 3.80-kg mass hanging from one end and a 3.15-kg mass hanging from the other end. The pulley is a uniform solid cylinder of radius 4.0 cm and mass 0.80 kg. If the bearings of they pulley were frictionless, what would be the acceleration...
  33. A

    Equation Questions for a gas powered engine driving a pulley system.

    I am building a prototype for an agricultural pulley system and I need help calculating how much horse power I need. The pulley system will need to drag a 400 lbs. object of a 45 degree incline for 150 feet. The static coefficient of friction is 0.1 and the kinetic friction is only 0.05...
  34. J

    Pulley System Problem with String Impulse (Atwood's Machine)

    Homework Statement Two particles of masses 8 kg and 5 kg are connected to the two ends of a light inextensible string which passes over a fixed smooth pulley. Initially each of the two particles are held at a position which is 5 m above a horizontal ground. The objects are then released from...
  35. J

    Pulley System Where String Breaks

    Homework Statement Two particles A and B, of masses 2m kg and m kg respectively, are connected by a light inextensible string which passes over a fixed smooth pulley. The system is RELEASED from REST, with both portions of the string vertical and taut, while A and B are at the SAME HEIGHT. 1...
  36. J

    Two Pulley System (Driver/Driven) power transmission.

    Homework Statement 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...
  37. N

    Calculate the speed of the Cylinder in the pulley system

    Homework Statement Each of the two systems is released from rest. Calculate the speed v of each 47-lb cylinder after the 38-lb cylinder has dropped 5.2 ft. The 17-lb cylinder of case (a) is replaced by a 17-lb force in case (b). I have attached an image of the question. Homework...
  38. I

    Find the mass of m1 on an inclined pulley system

    Homework Statement Two masses ##m_1## and ##m_2## are connected by a massless cord and a pulley, on a rough ramp, tilted at angle ∅ The pulley is massless and frictionless. The coefficient of kinetic friction between the ramp and m1 is ##μ_k.## Derive an expression for ##m_1,## given that...
  39. A

    Resultant force on a pulley system

    Homework Statement Could anyone give me an idea of how to start this problem to work out the resultant force's magnitude, direction and couple in the top (alternator) pulley? Does the 30° angle affect the equations? As all the notes I have seem to only have pulleys with the force at each...
  40. P

    For this pulley system, why is it m1g - T1-T2=m1a?

    Three objects with masses m1 = 66.0 kg, m2 = 37.4 kg, and m3 = 21.8 kg are hanging from ropes that run over pulleys. What is the acceleration of m1? (Take the upward direction to be positive.) So for the two outside blocks, I know that the forces acting on the blocks are T1=m2g+m2a, and...
  41. M

    Calculating the moment of inertia in a pulley system

    Homework Statement An object with a mass of m = 5.10 kg is attached to the free end of a light string wrapped around a reel of radius R = 0.250 m and mass M = 3.00 kg. The reel is a solid disk, free to rotate in a vertical plane about the horizontal axis passing through its center. The...
  42. E

    Calculating Speed of Blocks in Pulley System with Spring Compression

    Homework Statement A block of 4 kg hangs from an ideal string which passes by a pulley and is attached at the other end to a block of 6kg, which is in turn lying on a rough table of friction coefficion μ=0.2. The block on the table is pushed towards a spring with elastic constant k = 60 N/m...
  43. L

    Pulley system to lift container. How much force?

    1. I am stuck. Could anybody push me in the right direction? Best Regards Lasse
  44. P

    HW Lab PHYS101: Net torque of pulley system and meterstick position balance

    THANKS, I ONLY NEED HELP #2 NOW, PLEASE 10/31/12 @ 9:10 pm bumpHomework Statement 1)If the fulcrum of a 0.1 kg meter stick was placed at the 40 cm mark and a 200 g mass at the 0 cm mark, would it be possible to balance the meter stick with a 200 g mass on the long side of the meter stick? What...
  45. S

    Accelerating pulley system questions

    Homework Statement Two objects, masses 6.0 kg and 8.0 kg, are connected by a lightweight cord that passes over a massless, frictionless pulley as shown in the diagram. An upward force of 250.0 N acts on the axle of the pulley, causing the entire system to move upward (the pulley is still...
  46. V

    Statics: A pulley system in equilibrium

    Homework Statement Hi, I am confused by this physics question and I was wondering if someone could help me out. I have a system with 2 pulleys and 3 weights. They are all held together by one string, the two weights on the outside of the two pulleys, both weighing the same, hold up the...
  47. PhizKid

    Kinetic/potential energy with a pulley system

    Homework Statement This is the simplest example: But I have to generalize with more pulley things on it. How does the pulley affect the kinetic energy of the car on the air track, and the potential energy of the block pulling the car? Homework Equations Nothing quantitative...
  48. M

    Solving a pulley system (Dynamics)

    Solving a problem about a pulley system (dynamics) A 100 kg crate is supported by a rope which passes over a 25 kg pulley. A 2nd rope connects the pulley to the ceiling. The system is stationary. ƩFx=0 ƩFy=0 I am having problems setting up the free body diagram to start the problem!
  49. N

    What are common problems encountered when using a double pulley system?

    Homework Statement https://docs.google.com/file/d/0B65UbG8T0LS9SEFRTHhHZmR2NDA/edit Question 2 Homework Equations The Attempt at a Solution Well I tried to draw a diagram but I don't really know where to start tbh, I also can't my head around how 1200N of force only provides 600N...
  50. N

    Quick look over friction pulley system

    Homework Statement Objects with masses m1 = 12.0 kg and m2 = 4.00 kg are connected by a light string that passes over a frictionless pulley. If, when the system starts from rest, m2 falls 1.00 m in 1.70 s, determine the coefficient of kinetic friction between m1 and the table...
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