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. Abhimessi10

    Pulley-Block-Spring System: Understanding the Forces Acting on a Hanging Block

    Homework Statement [/B]Homework Equations [/B]The Attempt at a Solution In the second question at 5:32,why doesn't the block have a spring force.In FBD of 2nd block it should have been mg-(T+kx)=ma right?
  2. HydroMarioUSA

    Tension on Pulley HW: Block A & B Force Analysis

    Homework Statement Block B is positioned on a fixed incline. Attached to block B is a massless, ideal string that runs over a massless ideal pulley and is attached to a hanging block block A at the other end. The mass of block A is 2 kg and the mass of block B is 10 kg. The angle of the incline...
  3. Victoria_235

    How Does a Lift's Acceleration Affect the Pulley System Dynamics?

    Homework Statement Two blocks are attached by strings of negligible mass to a pulley with two radii R1=0.06 m and R2=0.08 m. The strings are wrapped around their respective radios so that the masses can move either up or down. The pulley has a moment of inertia I=0.0023 kgm2 , and is supported...
  4. I

    Pulley Acceleration and Tension Relations

    Homework Statement Determine bodies' acceleration if their masses are the following: m1 = 25kg, m2 = 1kg, m3 = 3kg and the Tension of the ropes. Friction is neglected, as well as the mass of the pulley. It is considered that the ropes are perfect. m1 = 25kg; m2=1kg; m3=3kg; ___________ a=...
  5. A

    Trouble understanding Newton's Third Law in Pulleys

    Hi everyone. I found this image online that made me question a couple of things that might be a bit humiliating to ask: I always thought that tension is simply a pulling force, meaning that the mass is suspended because the tension force pulling the mass is equal to the weight force of the...
  6. K

    Why Did I Get the Pulley Tension Forces Wrong?

    Homework Statement [/B]Homework Equations F = m*aThe Attempt at a Solution [/B] Hello, i think i understand d and e so only the first three tasks are important.a) a = (m2 - m1)/(m1 + m2) *g -> (5kg - 2kg)/(2kg+5kg) *10ms^-2 = 4.29 ms^-2 T = m1 (a+g) -> 2kg (4.29ms^-2 + 10ms^-2) = 28...
  7. E

    Two blocks on a surface and a pulley

    Homework Statement Everything that can be used is in the picture. μ is the coefficient of friction between both B and A and A and the surface. A is moving upwards the surface with a certain acceleration. B doesn't move in relative to the surface. 1. Why the direction of A's motion must be...
  8. jalalapeno

    Finding Tension and theta in a pulley system

    What I've attempted to do is resolve vertically and horizontally: T1sin(30)+T2sinΘ+T2=9g T2cosΘ=T1cos30 After that... I'm completely stuck. Any help would be appreciated, I've spent so long on this I bet I'm just missing one simple thing. Thanks in advance
  9. L

    Pulley Question : find tension in rope (Help )

    Homework Statement Homework Equations F = ma The Attempt at a Solution So , i drew a freebody diagram for the 6k gram block, and the tension to the right of I call T2. Therefore, the force of gravity component parallel to T2 is (6*9.8)sin30. Therefore, T2 is equal to this value which i...
  10. SciencyBoi

    Three Pulley - two masses system.

    Homework Statement The given system is released from rest. Assuming no friction, mass-less pulleys and ideal strings; calculate the accelerations of the pulleys. Homework Equations Constraint equations. F=ma The Attempt at a Solution Taking the above assumptions; And applying constraints...
  11. L

    Another pulley problem (answer check)

    Homework Statement Homework Equations Shown above The Attempt at a Solution Shown above. Since the normal force is just the force opposite to the surface (gravity force) , it's just mgcos(theta). [/B]
  12. L

    Pulley at an Angle Problem - Newton Forces

    Homework Statement Homework Equations Friction Force = normal force * static coefficient for friction Fnet = ma The Attempt at a Solution So i drew the free-body diagrams for both the objects...[/B] Im trying to figure out the tension in the 2nd free body diagram and i know that it's...
  13. L

    Pulley Problem with External Force?

    Homework Statement Homework Equations Seen above The Attempt at a Solution Why is the force acting on block B = N + P + W =0? ? Shouldn't it be B = -P-W+N? So that P = -W+N=0
  14. Jamie_Pi

    Blocks falling while attatched to pulley

    Homework Statement The two blocks, m1 = 3.3 kg and m2 = 4.8, in the figure below are connected by a massless rope that passes over a pulley. The pulley is 12 cm in diameter and has a mass of 2.0 kg. As the pulley turns, friction at the axle exerts a torque of magnitude 0.64 N · m. If the blocks...
  15. goonking

    Jamming a Pulley: Assessing Stress on Shaft & Hole

    A pulley-and-shaft is connected to a motor which applies torque to spin the pulley as shown below: Now imagine someone jams machine by sticking a broom into one of the holes of the pulley. I would imagine there would be normal stresses at the hole (location of jam) and torsional stress on the...
  16. M

    A system comprising blocks, a light frictionless pulley, and

    Homework Statement A system comprising blocks, a light frictionless pulley, and connecting ropes is shown. The 9-kg block is on a smooth horizontal table (μ = 0). The surfaces of the 12-kg block are rough, with μ = 0.30. In Fig. 5.7, the mass M is set so that it descends at constant velocity...
  17. 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...
  18. F

    Acceleration along a pulley with a ledge

    Homework Statement Homework Equations F = ma The Attempt at a Solution The solution to the problem is 1.12m/s^2. However, I don't know how they got to that number. Every way I do it I end up with 3.2m/s^2.
  19. parshyaa

    A few questions related to tension in a string

    Its getting hard for me to deal with the problems related to tension and reason behind this is not clear understanding of the concept so i have few questions on this. What causes tension in a rope/string(i think its related to electromagnetism, but i am not getting the clear idea behind this)...
  20. N

    Motor lowers a mass over a pulley, find acceleration of mass

    Homework Statement When the motor in the figure below lowers the m = 1200kg mass, it produces a tension of 1.15E+4N in the cable on the right side of the pulley. The pulley has a moment of inertia of 71.3kgm^2 and a radius of 0.794m. The cable rides over the pulley without slipping. Determine...
  21. T

    Understanding Tension on a Pulley

    Homework Statement Problem image: https://prnt.sc/gvhjso In this case I have to find the reaction forces at the point E (the Fx, Fy, and the Moment at point E) by using the given data. The 20kN forces at the load AC are concentrated, and are 1.8m far from each other. The tension of the cable is...
  22. D

    Tapered vs. Straight Shaft Pulley I/F

    Hi all Need help to determine if adapting a pulley from a tapered shaft to straight bore will work. Can the clamping force be calculated for a tapered shaft to bore i/f and straight shaft? I have a professionally modified Porsche crankshaft in which 10mm of the tapered end was cut off creating...
  23. Biker

    A pulley with a mass on a string

    Homework Statement Problem: ABC is a cable with length 5 m attached to both a and c. By neglecting the dimensions of the pulley, and if the pulley is stationary, Calculate: 1) x 2) Tension[/B] Homework Equations F net = 0[/B] The Attempt at a Solution I have two problems with this...
  24. S

    What is the Relationship Between Tension and Velocity in a Vibrating String?

    Homework Statement (Problem #1 on this page.)[/B] Homework Equations ##v=\sqrt { \frac { T }{ \mu } } =\lambda f## The Attempt at a Solution I don't think there is enough information, ##v=\sqrt { \frac { Mg }{ m/L } } ## m, the mass of the string is not given
  25. C

    MHB What are the Variables Needed to Solve a Pulley System Problem?

    Two blocks are connected by a massless rope as shown below. The mass of the block on the table is 5.4 kg and the hanging mass is 2.1 kg. The table and the pulley are frictionless. I need to find acceleration, the tension of the rope, and the speed when mass 2 hits the floor when it starts from...
  26. R

    Finding the Acceleration of masses on a pulley

    Homework Statement Masses M and m are connected to a system of strings and pulleys as shown in the diagram below. The strings are massless and inextensible, and the p ulleys are massless and frictionless. A: Find the accelerations for M and m (Hint: Think about these two questions: Do these two...
  27. H

    Tension from two carts & hanging object on pulley

    Homework Statement Hi. My problem (from my picture) is which string (A or B) has more tension when the 50g object accelerates down and both carts move left. The pulley and string can be considered massless and frictionless. Homework Equations Fnet = m*a The Attempt at a Solution My thinking...
  28. V

    What is the acceleration of the blocks in a pulley constraint problem?

    Homework Statement Need to find the acceleration of the blocks, all surfaces are smooth : https://drive.google.com/file/d/0B5bF4yPQOejoazhWeEgySmtfSnc/view?usp=drivesdk Homework Statement Need to find the acceleration of the blocks Homework Equations a1 + a2 + a3 =0 (acceleration of strings...
  29. V

    Peculiar Acceleration: Solving a Massless and Frictionless Pulley Problem

    Homework Statement All pulleys are massless and frictionless and string is massless . Find the acceleration of the two masses and the two pulleys . Homework EquationsThe Attempt at a Solution I will call the left mass A and right mass B and left pulley P and right pulley R . Acceleration...
  30. H

    3 masses and an inclined pulley system

    Homework Statement The tension between the 6 kg and 4 kg object as=2.1m/s Fnet = 40N assume 0.4 kinetic friction coefficent Homework Equations T1- Fnet = mas The Attempt at a Solution acceleration is negative because the object is decelerating as it goes up the slope so T1-40N = 6(-2.1) T1 =...
  31. U

    Angular momentum of a pulley system

    Homework Statement it is given in the image i uploaded Homework Equations L→=r→ × p→[/B] The Attempt at a Solution If the angular momentum of a particle is the cross product of the position vector of the particle from the axis and its linear momentum, how can the angular momentum of m1 and...
  32. A

    Friction Force with Incline and Pulley

    Homework Statement There is a mass m1 on an incline (angle α), connected to a pulley with a string, and on the other side of the pulley, after another string, there is a mass m2. See picture if it's unclear, I'm not sure how to express the problem. Anyway the plane has a friction coefficient...
  33. V

    Calculating force: pulley and gear on the same axle / shaft

    Dear Forum, Please see the attached file below. I have trouble understanding what happens at the light green gear which drives the big brown one. I read somewhere that the force that the belt applies on the surfaces of the two pulley's is the same, so 353, 68 Nm. The torque and rpm on both...
  34. J

    What Forces Act on a Pulley System with Two Masses?

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] When the right mass moves horizontally towards right , the verticle force acting on it is Mg - Tcosϑ , where ϑ is the angle which right string makes with verticle . The left mass experiences a force Mg - T . Since verticle...
  35. O

    Angular Acceleration of a Pulley with Mass

    Homework Statement A pulley hangs of mass, m, and radius, R, hangs from the ceiling. Two blocks of masses, m1 and m2 are connected by a massless, non-stretchable rope on the pulley (assume no slipping). What is the angular acceleration of the pulley and what is the ratio of the tension forces...
  36. snate

    What Determines the Maximal Elongation of a Spring in a Pulley System?

    Homework Statement 2 bricks of mass m are located near the edge of a smooth horizontal surface, they are connected by an ideal weightless ,unstretched spring with a length of l0 and spring constant k. The brick which is closer to the edge is connected to another brick of the same mass by an...
  37. B

    Torque of Pulley with Two Masses2

    Homework Statement Two weights are connected by a very light flexible cord that passes over a 40.0-N frictionless pulley of radius 0.300 m. Weight #1 is 125 N and Weight #2 is 75 N. The pulley is a solid uniform disk and is supported by a hook connected to the ceiling. What force does the...
  38. Alexander350

    Finding all the forces in this system

    Homework Statement [/B] I am trying to identify every force in this system and prove that it is in mechanical equilibrium when tan(θ)=⅓. Initially I had to solve it by finding when the derivative of potential with respect to θ was 0, but now I am just trying to resolve the forces. Homework...
  39. O

    Conservation of Energy: Pulley and Springs

    Homework Statement Two blocks are connected with a massless, non-stretchable rope, and connected to a spring that is fixed to a wall. One of the blocks is hanging from the side of the table, while the other lies on the table. The mass of each block is m=1.0 kg, spring stiffness is k=50 N/m...
  40. N

    What Is the Acceleration of Block B in a Two-Mass Pulley System?

    Homework Statement In the figure shown if the system is released from rest, acceleration of block B will be (a). g/2 (b). g/3 (c). 2g/3 (d). g/7 Homework Equations ma= F[net] taking the direction of motion as positive The Attempt at a Solution So my attempt was to first find tension in the...
  41. D

    Pulley system, calculate acceleration

    1. Homework Statement this is a pulley system, each masses are moving with acceleration with a1,a2,a3.. question) 1) How can i calculate the ratio a1:a2:a3 ? 2) How can i calculate the T(tenstion)? 2. Homework Equations a1,a2,a3: acceleration of each masses. g=10m/s2 weight of all pulleys...
  42. Deadawake

    Is Tension2 always smaller than Tension1 in a tension and pulley system?

    Homework Statement M = M There is another mass "m" attached to mass "M" with a rope There is an acceleration (clockwise) Does Tension2 smaller,bigger or equal to Tension1? Homework Equations F = ma The Attempt at a Solution So this is what I understand just by the logic: In any case -...
  43. J

    Perpendicular force pulley system

    i would like to know if the forces exerted by the load on pulley 1 and 2 are equal when the motor star running , or if in pulley 1 is exerted more force because the location of the load at the end of the lifting platform. The lifting platform only moves vertically, restricted by rails. What I...
  44. deuce123

    Forces help -- 2 masses, a pulley and friction....

    Homework Statement Determine a formula for the acceleration of the system shown in the figure(Figure 1) in terms of mA, mB, and the mass of the cord, mC. Assume f to be the fraction of the cord that is hanging down between mB and the pulley, and μk to be the coefficient of kinetic friction...
  45. V

    Newton's laws of motion -- finding the velocity of a Block in a pulley system

    Homework Statement Determine the speed with which block B rises in figures if the end of cord at A is pulled down with a speed of 2ms^-1 Homework Equations Given Velocity downwards at A=2m/s The Attempt at a Solution Really stuck... Couldn't even start the question solving...I know all...
  46. V

    Newton's laws of motion -- pulley system

    Homework Statement In the situation given all surfaces are friction less pulley is ideal and steering is light. Find accn of block 2 Homework Equations Given F=mg/2 The Attempt at a Solution .[/B] Got answer as G/2 instead of G/4 ...(actual answer is g/4) Since F=mg/2 and block 1 is hanging...
  47. V

    Newton's laws of motion -- Constaint motion

    Homework Statement In the following diagram a massless pulley is pulled by a constant force of magnitude P. There is no friction between the block and the floor. The acceleration produced in the block if mass m is? PIC ATTACHED Homework Equations Took a1/2=a2 where a1 is accn of block and a2...
  48. A

    Help with this pulley question please

    Homework Statement Two objects of equal masses A and B are connected to a system of pulleys as shown in the figure uploaded. The pulleys are assumed to be smooth. Calculate the acceleration of A. Homework Equations F=maThe Attempt at a Solution Mg-T=ma I can't figure out the second equation...
  49. 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?
  50. Mateus Buarque

    Simple Harmonic Motion and equilibrium of springs

    The figure below shows a system in equillibrium. The pulley and the springs (both with constants "k") are ideal. The period of oscillation of the mass A is given by: Relevant equations: F = -kx (SHM) I tried to do a "force diagram" and set up some geometric relations but it´s not working.
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