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. Saitama

    How does the tension in a pulley system change with different masses?

    Homework Statement In the arrangement shown in Fig. 1.18(see attachment) the mass of ball 1 is η=1.8 times as great as that of rod 2. The length of the latter is l = 100 cm. The masses of the pulleys and the threads, as well as the friction, are negligible. The ball is set on the same level as...
  2. P

    Finding the acceleration of a pulley system

    1. A pulley system consists of Mass A (400g) on a wooden ramp being pulled by Mass B (300g) which is suspended in the air. The board is placed on a table at an angle of 12 degrees. The following values are for the system: Hypotenuse(Length of board): 50cm, Height from table to board (a from...
  3. H

    What is the minimum length for x to lift the bucket 9 meters in 4 seconds?

    http://imgur.com/NMu80 http://imgur.com/NMu80 Hello! I have a problem to solve and I am not quite sure how to. In the linked image i have the values of G, F and D given. F stays constant and right angled towards the lever. The bucket needs to go up 9 meters in 4 seconds. What is the...
  4. E

    Motor in a pulley system with weight help (Sort of a dynamics problem)

    Homework Statement At the instant shown, point P on the cable has a velocity 12 m/s, which is increasing at the rate of 6m/s^2. Determine the power input of motor M at this instant if it operates with an efficiency of 0.8. The mass of the block A is 50kg. I've attached a picture of the...
  5. E

    Engineering Motor and Pulley System with weight help (Kind of a Dynamics Problem)

    Homework Statement At the instant shown, point P on the cable has a velocity 12 m/s, which is increasing at the rate of 6m/s^2. Determine the power input of motor M at this instant if it operates with an efficiency of 0.8. The mass of the block A is 50kg. I've attached a picture of the...
  6. F

    Acceleration and tension of pulley system

    Honestly I'm not sure if I've made any mistakes here, but I've been having considerable difficulty with tension problems. This is also the first pulley problem I've attempted, so I'm sure I've made a blunder or two somewhere. If someone could review what I've done so far that would be very...
  7. E

    Finding Tension T1 in a Pulley System

    A pulley is massless and frictionless. The masses 2 kg, 3 kg, and 6 kg are suspended as in the figure. (Figure Attached) What is the tension T1 in the string be- tween the two blocks on the left-hand side of the pulley? The acceleration of gravity is 9.8 m/s2 . Answer in units of N...
  8. T

    Pulley system (ideal pulley) Find the angle with vertical line

    Ideal pulley and strings, no friction.The pulley and the second string don't move. I need to find the numerical value of theta, the acceleration of the two blocks and the tensions.Accelerations and tension must be given in terms of m and g.I guess 2T1=T2 T1=m2*a m1*g-T1=m1*aTo find theta I need...
  9. T

    Find velocity of hanging block in a pulley system

    A pulley is set up on the edge of a desk. A light string connects a 10 kg block laying on the desk to a 4 kg block hanging off the pulley. The only significant friction is with the desk, and the coefficient of kinetic friction is 0.20. Use the law of conservation of energy to find the speed of...
  10. W

    Simple Pulley System with Two Masses

    Homework Statement http://imgur.com/Y1Dua r = 0.2m I = 1.4kg m^2 m1 = 2kg m2 = 5kg h = 4m Homework Equations Δ(Gravitational potential energy) = m1*g*h - m2*g*h Δ(Kinetic energy) = (1/2)*m1*v^2 + (1/2)*m2*v^2 + (1/2)*I*(v^2/r^2) The Attempt at a Solution System is...
  11. R

    Mechanics - Pulley system finding coefficient of friction

    Homework Statement Homework Equations I believe: F = m . a Ffriction = μs . N Ffriction = μs . mg . cosθ The Attempt at a Solution I don't quite get how the equations above would give me an answer to the minimum friction required so that the farmer doesn't slip. I know Fl =...
  12. S

    Two Masses in Pulley System (Rotational Dynamics)

    So I've been prepping for my Engineering Physics 1 final, and I've been having trouble with rotational motion problems, but this problem has been driving me crazy for the past two days: Homework Statement (I wanted to include a normal link to an image, but I'm a new member, so here's...
  13. T

    How to draw pulley system diagram to find the relationship between two objects?

    Homework Statement Here is the diagram and I need to find a relationship between the acceleration in block A and the acceleration in block B. http://dl.dropbox.com/u/64325990/HW%20Pictures/datum2.PNG The Attempt at a Solution Here is my diagram, which is wrong...
  14. R

    Frictionless pulley system: same tension changing masses

    Homework Statement An astronaut lands on a distant planet with an unknown gravitational field g’. On the bottom of his spaceship, he attaches an ideal frictionless pulley supported overhead with two light buckets hanging downwards, attached by a light rope. He places 24 kg of the same rock...
  15. Z

    Which pulley system requires the least force to lift the same weight?

    Homework Statement http://data.imagup.com/10/1146555432.jpg Homework Equations Force applied on the weight=F*(MA). The Attempt at a Solution i chosse the E system ...it has the greater mechanical advantage (MA)=3. MA(of A)=1, MA(of B)=2,MA(C)=2,MA(D)=2,MA(E)=3.. I hope my...
  16. D

    HELP Find the mass in this inclined pulley system, required to move the 2 masses

    In this problem they show a diagram of a pulley system with an inclined plane (25 degree incline). There is a box called m1=47kg resting on the incline plane and m1=35kg hanging on the vertical line. The question reads: The coefficient of friction between m1 and the surfvace of the inclined...
  17. J

    What Is the Minimum Mass Needed to Move the Block in a Pulley System?

    Homework Statement A block with mass, m1 = 5.5 kg rests on the surface of a horizontal table which has a coefficient of static friction of μs = 0.52. This block is connected to another block by a pulley system and it hangs vertically under the influence of gravity, g. The hanging block has...
  18. K

    Three objects on a hanging pulley system

    Homework Statement Three objects with masses m1 = 37.5 kg, m2 = 19.5 kg, and m3 = 11.1 kg are hanging from ropes that are redirected over pulleys. What is the acceleration of m1? Negative numbers for downward, and positive numbers for upward, please. There should be a diagram of what the...
  19. S

    Finding tension and acceleration in a 3 weight, 3 pulley system

    Homework Statement This is a "DOE" (Design of Experiment) problem. Basically, the construction is fairly simple. 3 pulleys, 2 on either side, and a free pulley with a weight suspended on it in the middle. Picture is available (don't mind my crappy paint skills, rope lengths are all...
  20. M

    Double Pulley Systems/Complex Pulley System Problems

    Hey.. This is a question I received as part of my homework Your great grandmother gave you an antique scale that her great grandmother gave to her. It consists of a square platform mounted on 4 identical springs. When you step on the platform, you compress the springs, causing the platform...
  21. L

    How Do You Calculate Tension in a Three-Mass Pulley System?

    Homework Statement In the figure below, M1=1.00 kg, M2=2.00 kg and M3=4.00 kg. Theta is 30.0°. The pulley and all surfaces are frictionless. Find the tension in the two strings and the direction (entire system to the left/counterclockwise or entire system to the right/clockwise) and...
  22. I

    Oscillation of a spring - pulley system

    A massless spring of constant k=196 N/m is used to suspend the mass M=1.45 kg (including the pulley), as shown in the attached figure. What is the frequency of simple harmonic motion? Relevant equations f = 1/period T = 2pi*sqrt(M/k) Tension = 1/2Mg What I tried... T(tension on...
  23. B

    Finding Tension in a Pulley System

    Homework Statement A crate is pulled up using frictionless pulleys in the manner shown in the figure. The angle is 45 degrees. The masses are, for the small pulley, m1=4.1 kg, for the traveling pulley, M2=6.7 kg, and for the crate, MC=45.8 kg. What is the minimum tension with which the...
  24. S

    Conservation of energy with a mass and pulley system.

    Homework Statement Two boxes are attached to opposite ends of a rope passing over a frictionless pulley as shown below. The mass of Box A is 15kg and the mass of box B is 12kg. The system is originally at rest with the bottom of box A at a height of o.85m above the floor. When the system is...
  25. V

    Solving Question 2: Pulley System Challenge

    Homework Statement The question is on the attached picture, it's question number 2! Homework Equations Dealing with pulleys The Attempt at a Solution
  26. T

    How Do Tensions in a Massless, Frictionless Pulley System Compare?

    A mass M in held in place by the applied force F and the pulley system shown below. The pulleys are massless and frictionless. Determine the tension in each section in each section of rope and the applied force F Taking upwards as positve -T1 - F = 0 T4 - T1 - T3 = 0 T2 + T3 - T5 = 0...
  27. S

    Finding mass within a pulley system. Finding coefficient of friction

    Ok so I'm in college upgrading, and doing my physics 20. I have a hand in assignment due Wednesday and I can't for the life of me figure out these two questions. 6. The 4.0kg block shown accelerates across a frictionless horizontal table at 1.5m/s2. Find the mass of object m1 A. 0.61kg B...
  28. A

    Pulley system: 2 pulleys and 3 mass

    Homework Statement Note: My textbook and first language is french, I am sorry if I mistranslated some terms. A friction-less rope goes around the fix pulley A. At one side of the rope, there is a mass M1. On the other side, there is a pulley of mass M2. Another friction-less rope goes...
  29. G

    Finding Forces and Work in a Pulley System

    Homework Statement Need some serious help with this one :O A box with a weight WA hangs in pulleys ,(see figure 1). Find the force to pull A up with constant speed and calculate the work which the tractive force F produces ( with the movement of s) and also the work and tractive force...
  30. A

    Forces: Wedge and Block Problem + Pulley System Problem

    Homework Statement 9) A 15 kg wedge is pushed along a frictionless surface. There is no friction between the wedge and the block. What force, F, is required to keep the block from sliding up or down the wedge? See attachment for diagram. 10) Find the tension, T. See attachment for diagram...
  31. E

    A pulley system with two objects stacked on one another

    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...
  32. H

    What is the restorative torque applied to the disk in a pulley system?

    Hi everybody, I was doing my physics homework but I found that I cannot figure out how to do it, here is the question: http://imageshack.us/photo/my-images/202/phyl.jpg/" I don't quite understand how to calculate the torsional spring constant, so explanation on part a is enough:D Thanks...
  33. A

    A very difficult question about a pulley system with friction

    Homework Statement See the picture Homework Equations The Attempt at a Solution This is a very difficult, can anyone guide me step by step to finish this question. First, let start with part(a) In order to find the ratio, it seems we need to have the motion equations first...
  34. F

    Solving a Pulley System: Mass M & Friction Forces

    Homework Statement An object of mass M=10kg is being pulled up by a system of pulleys. a)What force do you need to exert on point A for the object to move uniformly ? b) What force do you need to exert on point A, if the friction in each of the pullies is 0,5N and the pulleys are not massless -...
  35. F

    Tension in a Pulley System: Solving for Work Done by the Tension Force

    Homework Statement Hi. My question is only regarding the early step in this problem that solves for tension. Here is the question: "In a pulley system where masses m and M are connected by a rope over a massless and frictionless pulley, find the work done by the tension force in lifting mass...
  36. P

    Tension in 3 Pulley System Homework

    Homework Statement (Kleppner & Kolenkow- An Introduction to Mechanics - 2.15) The image shows the setup. The task is to find the tension in the rope. The coefficient of friction of the sliding blocks with the surface is \mu, and the string is of constant length. Homework Equations Newton's...
  37. T

    Newton's Laws question : On springs and pulley system

    A Particle is attached by a string to a point in a rough inclined plane of elevation \theta. Co-efficient of friction is \mu. Originally, the string is unstretched and lay along the line of greatest slope.Prove that the condition for particle to oscillate is \mu < 1/3tan\theta. Note : Tension...
  38. K

    Pulley system with 2 inclined planes on either side, a block, and a cylinder

    Homework Statement Two inclined planes on either side of a frictionless pulley have angles theta (30 degrees) and phi (60 degrees). On the theta plane is a circular solid cylinder of mass M (1.2 kg) and radius R (.2 m). It is connected by a weightless rope and over the pulley to the other...
  39. E

    Net Torque / Rotational Dynamics Pulley System help

    Homework Statement A uniform, solid cylinder with mass M and radius 2R rests on a horizontal tabletop. A string is attached by a yoke to a frictionless axle through the center of the cylinder so that the cylinder can rotate about the axle. The string runs over a disk-shaped pulley with mass M...
  40. M

    How Do You Calculate the Force Needed to Turn a Handle in a Pulley System?

    i have a simple pulley with a mass a one side and turning handle at the other. i can calculate the tension in the pulley but i am not sure how to calculate the force required to turn the handle and move the mass, or is this simply just equal to the tension in the system?
  41. G

    Forces in the triangle and pulley system

    Two blocks are connected by a string-one on an incline, the rope draped over a pulley, and one hanging from the string. The smooth inclined surface makes an angle of 35 with the horizontal, and the block on the incline has a mass of 5.7 kg. The mass of the hanging block is 3.2kg. Find the...
  42. I

    Does Pulley Mass Affect Rope Tension Symmetry?

    Hi there, If a pulley system made of 2 same mass blocks (on a a table, one hanging), a disk pulley with mass but no friction on the string nor pulley axis, does it mean that the Tension on the rope is the same on either side of the rope? Everywhere I've read implies this, and it makes sense...
  43. E

    Work in Pulley System: What is the Total Work Done on the 20.0-N Block?

    Homework Statement Two blocks are connected by a very light string passing over a massless and frictionless pulley (Figure ). The 20.0-N block moves 75.0cm to the right and the 12.0-N block moves 75.0cm downward. Find the total work done on 20.0-N block if there is no friction between the...
  44. M

    Finding W1 & W2 Given Frictionless Pulley System

    In the figure shown the pulley are frictionless and the system hangs at equilibrium. If w3, the weight of the object on the right is 200N, what are the values of w1 and w2? http://img228.imageshack.us/i/74717268.png/ http://img228.imageshack.us/img228/2605/74717268.th.png Uploaded with...
  45. D

    Mass acceleration - pulley system - friction

    Homework Statement In Figure P4.25, m1 = 10.5 kg and m2 = 3.5 kg. The coefficient of static friction between m1 and the horizontal surface is 0.60 while the coefficient of kinetic friction is 0.30. If the system is set in motion with m2 moving downward, what will be the acceleration of the...
  46. M

    Acceleration of pulley system physics problem

    Homework Statement In the figure, find an expression for the acceleration of m1 (assume that the table is frictionless).Homework Equations The Attempt at a Solution That picture of the second mass is stumping me because I have no idea what the heck is going on. It seems as if the second mass...
  47. M

    Conservation of Energy within a pulley system

    Homework Statement Two objects are connected by a light string passing over a light frictionless pulley as shown in the figure. the 5.87 kg object is released from rest at a point 2.55m above the floor. The acceleration of gravity is 9.8 m/s^2. What is the speed of each object at the instant...
  48. D

    Pulley System equilibrium problem

    Homework Statement If the system below is in equilibrium, show that tan(Theta) = 1 + (2M/m) Homework Equations F=ma The Attempt at a Solution I was pretty confused with this problem. All I think I know is that the force being pulled downward on M is F=mg/2. Can someone...
  49. T

    Pulley System: Calculate Work, Force, Efficiency

    Homework Statement The diagram shows a pulley system consisting of two pulleys of weights 10 N each. The system is doing work to lift a load of 100N upwards for 10m at constant speed. Calculate (1) the total work done by the pulley system. (2) the magnitude of force,F (3) the efficiency...
  50. A

    Calculating Tension in a Pulley System with Three Masses

    We have the following system in ideal condition (pulleys and rope are mass-less and frictionless) We need to find the conditions in which M3 will go downwards... Ok so here's what I did: M3g > T And this is what I'm not sure of: T=(M1g + 0.5M2g + M3g)/3 So the answer which I came to was...
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