What is Atwood machine: Definition and 161 Discussions

The Atwood machine (or Atwood's machine) was invented in 1784 by the English mathematician George Atwood as a laboratory experiment to verify the mechanical laws of motion with constant acceleration. Atwood's machine is a common classroom demonstration used to illustrate principles of classical mechanics.
The ideal Atwood machine consists of two objects of mass m1 and m2, connected by an inextensible massless string over an ideal massless pulley.Both masses experience uniform acceleration. When m1 = m2, the machine is in neutral equilibrium regardless of the position of the weights.

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  1. A

    Atwood machine, solve for angular acceleration

    Homework Statement The goal is to solve for angular acceleration with the end variables being m1,m2,m3, R, r, g. M2 > M1. An atwood machine is a pulley with 2 masses, one on each side. Homework Equations Tnet = I * angular acceleration Fnet = ma The Attempt at a Solution I know...
  2. I

    Mechanics - massive pulley, Atwood machine or similar

    hi, why does a massive pulley cause different tensions in a length of cable? I've looked for answers but got only that "the pulley needs to be lifted". Couldn't really picture it. Some maths would be nice :smile: cheers!
  3. B

    How do the masses and pulleys affect the motion of a double Atwood machine?

    Homework Statement My question is about a double atwood machine like this: http://farside.ph.utexas.edu/teaching/336k/Newton/img1915.png Now imagine that m1 = 5m, m2=2m, m3=3m My question is: why does the upper pulley rotate despite the fact that the masses on either side are...
  4. A

    Atwood machine problem (speed of mases after they have moved through 1.45 m)

    Homework Statement An Atwood machine has a mas of 2.50 Kg connected by a light string to a mass of 7.00 Kg over a pulley with a moment of inertia of 0.0652 kg m^2 and a radius of 11.3 cm. If the system is released from rest, what is the speed of the masses after they have moved 1.45 m? (Hint...
  5. J

    How Accurate Can an Atwood Machine Measure Gravity?

    Homework Statement Consider the Atwood's machine of Lecture 8. We wish to use this machine to measure our local acceleration of gravity with an accuracy of 5% [i.e. (Delta g)/g = 0.05]. To begin, suppose we let the mass m_1 fall through a distance L. 3.1 Find an expression for the...
  6. W

    Atwood Machine: Reduce Exp Errors By Stabilizing Masses

    Homework Statement String that is equal in length to the string connecting the pulley is sometimes tied to the bottoms of the two masses, where it hangs suspended between them. Explain why this would reduce experimental errors. Homework Equations The Attempt at a Solution I'm...
  7. C

    Rotational Inertia of an Atwood Machine

    1. In the figure below, the pulley is a solid disk of mass M and radius R with rotational inertia .5MR. Two blocks, one of mass m1 and one of mass m2 hang from either side of the pulley by a light cord. Initially, the system is at rest with block 1 on the floor and block 2 at height h above...
  8. H

    Atwood Machine: Forces & Motion True/False Quiz

    Homework Statement A frictionless, massless pulley is attached to the ceiling, in a gravity field g = 9.81 m/s2. Mass Mb is greater than mass Ma. The tensions Tx,Ty, Tz, and the constant g are magnitudes. (Select a response for each statement.) Please look at this pic...
  9. C

    Atwood Machine Help: Problem 1 Harvard

    Homework Statement http://isites.harvard.edu/fs/docs/icb.topic725237.files/problemset3_2010.pdf (Problem 1) Homework Equations f=ma, string conservation The Attempt at a Solution I'm not really sure how to do this. I know that the t of the string on the left is equal to the two...
  10. C

    What mistake did the author make in their Atwood machine problem?

    Homework Statement http://imgur.com/a2fLm Homework Equations F = ma is it The Attempt at a Solution The problem I had is that it's attached to the floor all of a sudden. Never before have we had Atwood problems like this, and I can't find any online... I drew out the free body...
  11. T

    Atwood machine problem - symbolically solving for mass?

    atwood machine problem -- symbolically solving for mass? Homework Statement Symbolically solve the equation derived for the acceleration of the Atwood's machine in part 1, A-3 for the mass m in terms of M, g, and the acceleration, a. (No numbers.) This question is part of a lab, so of...
  12. P

    What is the explanation for the 4m mass going down in a double Atwood machine?

    Homework Statement I have a double Atwood machine; on left side there is a heavy thing which weight 4m, on right side there is another circle (this circle which go around in atwood machine) and on left there is heavy thing which weight m, on right - mass which weight 3m. Now the 3m thing starts...
  13. A

    How Does Friction Affect Torque in an Atwood Machine?

    Homework Statement Two masses are suspended from a pulley of mass m supported by an axle (Atwood machine). What is the net torque acting on the pulley wheel in terms of T1 and T2? There is friction between pulley and rope. Ropes are massless and pulley can rotate without friction about its own...
  14. P

    How Do You Calculate Acceleration in an Atwood Machine?

    Homework Statement ATWOOD MACHINE LAB Draw a free body diagram of m1 and another free body diagram of m2. Using these diagrams, apply Newton’s second law to each mass. Assume that the tension is the same on each mass and that they have the same acceleration. From these two equations, find...
  15. K

    Calculating Tension in Atwood Machine

    Homework Statement I'm looking at how to calculate the tension in the ropes in an Atwood machine (two masses hanging on either side of a pulley, with mass 2 on the right side). We were told, for connected objects, that it was easiest to treat the two objects as a system and use a curved...
  16. W

    Applying force vs applying weight to an atwood machine

    I have two problems which appear equivalent, but apparently they are not. The first one is this: M, a solid cylinder (M=1.75 kg, R=0.131 m) pivots on a thin, fixed, frictionless bearing. A string wrapped around the cylinder pulls downward with a force F which equals the weight of a 0.750 kg...
  17. J

    Calculating Acceleration of Mass in Atwood Machine

    1.In the diagram above, the pulley is frictionless and the ropes are massless. Given that m1 = 14.5 kg and m2 = 23.0 kg, calculate the acceleration of m2 downwards. What is the magnitude of the tension in the string...
  18. M

    Double Atwood Machine (With one end of the string connected to the ground)

    [b]1. Homework Statement [/b ]http://teacher.pas.rochester.edu/phy121/PracticeExams/FinalExam/FinalExam_files/image015.jpg This is not the exact picture, instead of having M1 there let end of the string be connected to the ground instead Find the tensions and accelerations Homework...
  19. J

    Atwood Machine Related Question

    Homework Statement A 59-kg window-washer stands on a 17-kg platform. The platform is fixed to a rope that passes over a pulley attached to the ceiling, which allows the window-washer to raise himself and the platform. (a) To accelerate himself and the platform at a rate of 0.84 m/s2, with...
  20. T

    How Do You Calculate Tension and Normal Force in an Atwood Machine?

    Homework Statement For this problem the atwood's machine is used. There is a simulation where, m1 is 1.0 kg and m2 is 1.1 kg. Mass m2 rests on the floor that exerts a normal force, FN, on m2. There is no motion (i.e.. the system is in equilibrium). What is the normal force, FN, and what is...
  21. S

    Find acceleration of a modified atwood machine

    Homework Statement An Atwood machine is constructed using a disk of mass 2.4 and radius 23.4. What is the acceleration of the system? The acceleration of gravity is 9.8 . Picture: http://img.photobucket.com/albums/v356/SfTbLxMiShi/atwood.jpg Homework Equations \sumF=ma torque = I(alpha)...
  22. P

    Linear acceleration using atwood machine

    Homework Statement An Atwood machine is constructed using a hoop with spokes of negligible mass. The 2.4 kg mass of the pulley is concentrated on its rim, which is a distance 20.9 cm from the axle. The mass on the right is 1.36 kg and on the left is 1.79 kg. What is the magnitude...
  23. O

    Modiefied Atwood Machine Problem.

    1. A wheel is rotating about an axis perpendicular to the plane of the wheel and passing through the center of the wheel. The angular speed of the wheel is increasing at a constant rate. Point A is on the rim of the wheel and point B is midway between the rim and the center of the wheel. For...
  24. A

    Atwood Machine with a twist - String with Mass

    Hello all. I've read the forums a few times for help but this is my first time posting, so please bear with me if I make a few mistakes. I'm studying for my final undergrad assessment, so I thought a good way to study would be to make "advanced" versions of problems I'm already familiar with...
  25. B

    Why Does the Atwood Machine Accelerate Faster with Increased Mass on One Side?

    Homework Statement Well gravity's acceleration on objects is 9.8 m/s^2 and the question is why the Atwood Wheel moves faster as the mass on side is increased. Homework Equations N/A The Attempt at a Solution I am thinking it has something to do with inertia and the torque of the...
  26. P

    Atwood machine probolem: Apply Lagrangian equations

    Homework Statement A uniform circular pulley of mass 2m can rotate freely about its axis of symmetry which is fixed in a horizontal position. Two masses m, 3m are connected by a massless string which passes over the pulley without slipping. The whole system undergoes planar motion with the...
  27. R

    Atwood Machine, Rotational Inertia, and Energy

    In the figure below, the pulley is a solid disk of mass M and radius R, with rotational inertia (MR2)/2. Two blocks, one of mass m1, and one of mass m2, hang from either side of the pulley by a light cord. Initially, the system is at rest, with Block 1 on the floor and Block 2 held at height h...
  28. I

    Solving Atwood Machine Lab: Determining Acceleration

    Homework Statement Useing atwood machine, determine acceleration, knowing weight of mass to be pulled and mass pulling, distance mass travels, and information provided by photogate[which we don't understand what exactly this information is] Homework Equations Unknown... The Attempt at a...
  29. P

    Atwood Machine: Find m1's Descent and Velocity

    Homework Statement In the Atwood machine shown below, m1 = 2.00 kg and m2 = 7.50 kg. The masses of the pulley and string are negligible by comparison. The pulley turns without friction and the string does not stretch. The lighter object is released with a sharp push that sets it into motion at...
  30. B

    Atwood Machine Lab: Solving Force Equations w/ Friction

    First of all, I'd just like to apologize for me asking for help in my first post. I know that seems kind of lame. Homework Statement The lab involves an Atwood's machine which is basically two masses attached to some kind of pulley system so that if the masses are equal, the system will be...
  31. S

    Finding Gravitational Acceleration with Atwood Machine Graphs

    Homework Statement I have 3 graphs: accleration vs. total mass, acceleration vs. mass difference, and acceleration vs. inverse total mass. How can I get the gravitational acceleration from these 3 graphs ? I am doing a lab report on word and excel Homework Equations I don't...
  32. W

    What Is the Acceleration in an Atwood Machine with Blocks of 396 N and 180 N?

    In the drawing, there are two blocks connected by a rope and pulley. One block is on the table while the other is hanging off of the table. Block A, with a weight of 396 N, is on the table. Block B is hanging off of the table, and has a weight of 180 N. Ignore all frictional effects and assume...
  33. A

    How Does a Cat Affect the Acceleration of a Modified Atwood Machine?

    Homework Statement Given in this problem is a modified Atwood Machine (block A sits on a horizontal surface with a massless rope attached which goes horizontally over a frictionless pully attached to the edge of the "cliff" which is attached downward to block B) W of A = 45.0 N, W of...
  34. D

    How Is Tension Calculated in an Atwood Machine with Equal Masses?

    Homework Statement In an atwood machine which is a pulley with two wieghts attached to it (m1 and m2), m1= m2, how much tension is found on the string? I thought that it would be zero tension on the string but that appeared to be wrong. How would you solve it? The Attempt at a Solution
  35. S

    Help with an angled atwood machine problem

    Hey Guys, I have attached my problem and all my work for it. The work presented in my handwriting is the attempt I figure most accurate. All my other attempts were experimental to no avail :( I think I must be overlooking something really basic. Any assistance or pointers are greatly...
  36. B

    Atwood machine mass accleration problem

    Homework Statement A light pulley can rotate freely about its axis of symmetry which is fixed in a horizontal position. A massless inextensible string passes over a pulley . At one end the string carries a mass 4m, while the other end supports a second massless pulley. A second string...
  37. Y

    Double Atwood Machine and acceleration

    Homework Statement The double Atwood machine shown in the figure has frictionless, massless pulleys and cords. http://session.masteringphysics.com/problemAsset/1057076/4/GIANCOLI.ch04.p56.jpg Determine the acceleration of masses mA, mB, and mC. Homework Equations F=ma The Attempt...
  38. R

    Double Atwood Machine and tension

    Homework Statement Find the tension in the string attached to mass 1 and mass 3. Find the acceleration of masses 1,2, and 3. The problem looks similar to the attached image except m1 and m2 are leveled. Express the answers in the given quantities and constants. I will call the tension in the...
  39. J

    Non-ideal atwood machine problem

    [SOLVED] non-ideal atwood machine problem Homework Statement Atwood machine. mass a is 19kg and mass b is 9 kg the pulley itself has diameter of 15cm and mass of 41kg mass A and b are release from rest. How far does mass A move in 2 sec? Homework Equations I = 1/2 mr^2 The...
  40. R

    Why Do Accelerations Differ in These Atwood Machine Configurations?

    Homework Statement In the three figures given in the attachment consisting of three atwood machines with, the blocks A, B and C of mass m have accelerations a1, a2 and a3 respectively.F1 and F2 are external forces of magnitude 2mg and mg acting on the first and third diagrams...
  41. ~christina~

    Atwood Machine and block acceleration

    [SOLVED] Atwood Machine Homework Statement A pulley which is mounted in horizontal frictionless bearings, has a radius of 5.00 cm. One block has mass M = 500 g and the other has mass m = 460 g. When released from rest, the more massive block falls 75 cm in 5.00 s (without the cord...
  42. N

    Atwood machine - find kinetic energy

    1) Massess of 1.00kg and 1.01kg are suspended in a frictionless Atwood machine a) Find acceleration of the 1.010kg mass b) Find the total kinetic energy of the masses 2.50s after being released So for a I set up an equation where a= (1.01-1.00)...
  43. ~christina~

    Complete the statement (relates to the atwood machine)

    Homework Statement Completing sentences... When the unbalanced force increases (total mass remaining constant), the acceleration of the system increases When the total mass that is accelerating increases (unbalanced force remains constant), the acceleration of the total system decreases...
  44. ~christina~

    Atwood Machine Lab calculations

    Homework Statement My results are coming out funny and I was wondering if I was doing something wrong. I have to find acceleration due to gravity. one of my values ... m2 (decending mass) = 60g m1(ascending mass)= 50g distance traveled= 95.3cm or .953m time traveled average=...
  45. R

    Calculating Tension in a Two Pulley Atwood Machine

    Homework Statement Calculate the force of tension in the string of an Atwood machine with masses (1 - on right) 69.95 grams, (2 - middle) 80.11 grams, and (3 - on right) 60.28 grams. When this value is determined, verify that the net force in the atwood machine is equal to zero....\...|.../...
  46. G

    Atwood machine Force & Motion problem

    Homework Statement Figure 5-53 shows Atwood's machine, in which two containers are connected by a cord (of negligible mass) passing over a frictionless pulley (also of negligible mass). At time t = 0, container 1 has mass 1.30kg and container 2 has mass 2.80kg, but container 1 is losing...
  47. J

    What is the tension in an Atwood machine when one mass is infinitely large?

    An Atwood machine consists of two blocks (of masses m_1 and m_2) tied together with a massless rope that passes over a fixed, perfect (massless and frictionless) pulley. For all parts of this problem, take upward to be the positive direction and take the gravitational constant, g, to be...
  48. D

    Atwood machine pully problem with a twist

    Homework Statement A simple pulley has two masses on either end, one M1 and one M2. It is easy to find the acceleration of the two masses, and the tension on the rope suspending these masses. The pulley is suspended by a cord, however, and the question asks to find the tension in this cord...
  49. C

    Atwood's Machine Simulation: Determining Height with Given Masses

    help! atwood machine The two masses in the Atwood's machine shown in the figure below are initially at rest at the same height. After they are released, the large mass, m2, falls through a height h and hits the floor, and the small mass, m1, rises through a height h. In this Atwood's...
  50. C

    Atwood Machine: Is g = 9.8 m/s^2?

    Homework Statement Simple question I'm sure, but I want clarification if possible. If you do an experiment with the Atwood machine and you need to calculate 'g', should it be close to 9.8 m/s^2 ? Homework Equations No equations necessary, theoretical question. I would think the Atwood...
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