What is Mechanical advantage: Definition and 67 Discussions

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force. The model for this is the law of the lever. Machine components designed to manage forces and movement in this way are called mechanisms.
An ideal mechanism transmits power without adding to or subtracting from it. This means the ideal mechanism does not include a power source, is frictionless, and is constructed from rigid bodies that do not deflect or wear. The performance of a real system relative to this ideal is expressed in terms of efficiency factors that take into account departures from the ideal.

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  1. enigmaticbacon

    Converting Effective Mechanical Load to Newtons (Capybara)

    Hello again! I've found the capybara's EMA to be 0.71. Their mass to be 55kg. And their average speed to be ~3.0km/h. I want to figure out how many capybaras it would take to overcome Friction * Normal force of ~125,000N. How would I go about doing that...
  2. A

    I Understanding the physics of a bosun's chair and mechanical advantage

    I had a homework question recently where I had gotten a bosun chair question wrong. It is the exact question found in this youtube video (with the values changed). I am struggling to understand the way 2T is arrived at here (though I do understand this is an example of mechanical advantage)...
  3. Handysmurf

    I need some help with mechanical advantage (pulleys)

    I'm wanting to get a winch for my truck for vehicle recovery, but they are expensive. I know if I get a couple of snatch block pulleys, I can get a "smaller" (and less expensive) winch. My problem is that I don't know if the cable and pulleys need to be rated at or above the winch capacity, or...
  4. B

    Engineering Velocity Ratio, mechanical advantage, Efficiency of a screw jack

    Hello, I have completed the question below. I am just unsure on whether i am correct or not. I am unsure on Mechanical Advantage. As i have seen a few different equations. Question: Answer: a) Velocity Ratio = $$\frac{\text{Distance Moved By Effort}}{\text{Distance Moved By Load}}$$...
  5. F

    Mechanical Advantage of a pulley with horizontal effort

    How will the MA of a fixed pulley change if I apply the effort horizontally? Intuitively, I feel horizontal effort should be lesser effort than vertical effort.
  6. Rolacycle

    Mechanical advantage of a moving pulley vs an anchored pulley

    This is deer feeder pulley system I plan to make unless there is more efficient way to use the same 6 pulleys and pull load centered between the two poles
  7. G

    Mechanical Advantage of a Compound Wedge

    Length of wedge/width of wedge = mechanical advantage
  8. E

    Analyzing Tensions in a Pulley System: Understanding Mechanical Advantage

    I asume the upper right pulley wire loads will be split in two equally. Therefore, the sum of the loads above pulley equal T1+T2?. To me it appears as if the setup is almost like a 2 to 1 ratio. However, the wires on the left side which are anchored, split the load of the other half of the 2 to...
  9. E

    Mechanical advantage of a pulley system

    I don't know how the bottom two pulleys affect the top one. From what I know, the three ropes should have the same tension, the force of the body, divided between them. So if we take top one, it should have that tension on both sides, but also should support the other two pulleys below it. That...
  10. E

    Mechanical Advantage for an Ebike Trailer

    Hello everyone! I am trying to figure out a work load / Pulling ability of trailers for the company I work for. We produce Electric bikes that have attachable utility trailers.. The general Wattage output for these E-bikes is 1000w. The trailers Mechanical advantage = 62.15MA. (WR=11 & AR=...
  11. NewEnglander

    Compound lever: Best fulcrum location to increase mechanical advantage

    Good morning all, Ever since I encountered biomass brick presses I've had a renewed fascination with the use of compound levers to increase mechanical advantage. So my question is about the fulcrum location and its impact on MA. Let's say we have a simple class 1 lever A and we wish to...
  12. BMR

    Mechanical Advantage vs. Lever vs. Human Error

    This is my first post here, so pardon if forum guidelines/criteria require this to be designated elsewhere. I am designing a clamp mechanism utilizing lever mechanics, and I am getting conflicting info regarding Mechanical Advantage and the Law of 1st Class Levers. Regarding MA, knowing that...
  13. C

    What is the Mechanical Advantage of this lever? (for pulling tree stumps)

    I am interested in building a lever system for pulling up small tree stumps. I have seen this demonstrated on youtube videos. For example... However, I am more interested in calculating the various forces and mechanical advantage for such a system so I can figure out the best lever length...
  14. powdernose

    Mechanical Advantage in a crank system

    I am not a student btw, this is seeking extra knowledge regarding a hobby of mine, and it has been too long since I've tried to solve a physics problem. 1. Homework Statement I have the above system in which Lever L (200mm) applies force to a crank D (diameter 33mm), which has a reverse...
  15. L

    Does the mechanical advantage change if the load applies force?

    Hello, I am here to ask if anyone would help answer a question for me, in regards to a simple pulley system. The question is, does the mechanical advantage of a system change if the load is also the what is applying force to the system? Thank you for any answer you choose to give.
  16. Armando Valle

    How Do You Calculate Mechanical Advantage in a Nail Puller?

    What is the mechanical advantage of a nail puller where you exert a force 45 cm from the pivot and the nail is 1.8 cm on the other side? What minimum force must you exert to apply a force of 1250 N to the nail?Homework Equations 2. Homework Equations MA= FO/FI * LI/LO The Attempt at a Solution...
  17. B

    Mechanical advantage: lever arm

    Homework Statement In order to lift the 30 kg mass, a Force F is applied to the massless meter stick shown below. How much weight must the fulcrum bear if the mass is to be lifted? Homework Equations R/E = l/L The Attempt at a Solution So I began with the formula above and this is my set up...
  18. D

    Design of a Lightweight Waterproof (IP 67/68) Winch

    Hello, I am currently designing a lightweight waterproof winch system using off the shelf electrical or hand winches. My problem is that most electric winches that are waterproof are too heavy (design weight limit ~10lbs) and have a much higher force rating than needed (design max force ~500...
  19. Travis McWilliams

    Linear force > Angular torque > Mechanical advantage

    Guys, I'm trying to figure some stuff out, but I'm stumped. I need to figure the what my output would be. I'm applying linear force via hydraulic cylinder. The cylinder will turn a "gear" and in turn turn another. The "gear" is not necessarily a gear, it and the hydraulic cylinder will mate...
  20. BensonCa

    What is the force required to hold a pizza peel level with a pizza on it?

    Homework Statement A "peel" is a flat, long-handled shovel that a pizzaiolo uses to slide pizzas into and out of an oven. If a peel is 1.7m long and has a mass of 2.4kg and is carrying a pizza of mass 1.1kg as shown, what force must the pizzaiolo apply with his forward hand to hold the peel...
  21. R

    Ideal Mechanical Advantage of this bicycle?

    A bicycle wheel has a diameter of 73cm and is driven by a chain on a gear of 8.5cm diameter What is the ideal mechanical advantage? I know that IMA=de/dr But I'm not sure which one is de and which one is dr.
  22. UMath1

    Mechanical Advantage in absence of resistance or load

    I want to understand what happens to the energy inputted into a simple machine if there is no resistance or load. For example, let's say you have a U-shaped tube of water with greater surface area on the left side. If a piston applies pressure to the left side and there is no piston on the right...
  23. C

    Mechanical advantage of a mountain climber (pulley)

    Hi I have a hard time undersanding the mechanical advantage of this pulley system (in the video below): I understand that when a person is holding you, then the mechanical advantage is 2, because 50% of the weight or Load is on the rope going from the harness to the top left anchor point, and...
  24. UMath1

    Bicycles and Mechanical Advantage

    I am trying to understand how mechanical advantage works in a bicycle but I am still a little confused. I understand that the force applied to the pedal goes first to the crank sprocket which then applies a force to the chain at its radius which is the then applied to the gear at the wheel...
  25. B

    Mechanical advantage ideal systems

    Homework Statement An engineer with mass 100 kg has designed an ideal mechanical advantage machine shown below. Platforms 1 and 2 are attached to the machine. When he steps on platform 1, platform 2 rises straight up. The maximum weight that he can lift using his machine in this manner is...
  26. jmay4096

    Need Help Understanding Mechanical Advantage of Chain Mechanism

    Hi guys and girls this my first post! Hope i got it in the right place. I need help understanding the mechanical advantage of this mechanism. The top sprocket is the input power the bottom sprocket is an idler the attachment on the chain is the output. Help!
  27. G

    Mechanical Advantage of a 4-bar

    Alright, the problem at a glance is rather simple: find the mechanical advantage at two given values of θ2. Given: rO2A = r2 r02C = rin rAB = r3 rO4B = r4 rO4D = rout rO2O4 = r1 θ1 = 135° Find: Mechanical advantage when θ2 is equal to 104°, and when θ2 is equal to 91°. Equations to use: Mech...
  28. H

    Mechanical Advantage and What it really means (question inside)

    Homework Statement The question is as follows: A man of mass 100kg is placed onto platform 1. The maximum weight that he can lift using this machine is twice his own weight (200kg*g). The mechanical advantage of the machine is constant. If the mass of the object is 100kg, 1) what is the...
  29. L

    Mechanical advantage machines

    I've been at this problem for a good hour now and I just can't figure it out :bugeye: Please help me think through this! It is a very difficult problem in my opinion. Or maybe I'm just missing a fundamental point...Thanks in advance...
  30. K

    Does the mechanical advantage of a pulley change when lifting yourself

    So basically, at my work at a science center, we have this exhibit where you lift yourself using different pulleys. I noticed that the pulleys were labeled wrong. They should have been, 1/2, 1/3, and 1/5 but were labeled, 1/3, 1/4, and 1/6. I brought this up with management and received an email...
  31. E

    How a movable pulley increases mechanical advantage?

    Firstly, I'm sorry for posting this here it seems like the best place possible, but I'm not quite so sure I didn't see a section for civil engineering. So I don't understand why a movable pulley increases the mechanical advantage. This occurs in a situation when one end of the string is fixed...
  32. T

    How do gears provide a mechanical advantage?

    For example in this video at 5:00: They show by turning the gear with little force allows for one to move a VERY HEAVY gate to operate the sea locks. I don't understand how this is possible. Could anyone please explain the physics/theory behind this? Thanks!
  33. M

    Elementary mechanical advantage question

    I would be much obliged if the engineers on the forum could answer the following query regarding mechanical advantage. I don't require exact calculations or anything, just a quick yes or no, along with some simple KISS type explanation will be gratefully received. So, we have a situation in...
  34. H

    Mechanical advantage and force analysis of complex pulley systems

    Homework Statement These are two of the excercises where I'm supposed to calculate the mechanical advantage of the pulley systems. Excuse the crude MS paint drawings, I do not have access to a scanner or a proper camera. The red dots are where two cables connect. The Attempt at a...
  35. A

    Mechanical advantage of a crane

    Consider the following picture, where the same platform and man is being lifted by a crane and by the man standing the platform, who can pull on a rope connected to a pulley in the ceiling. My question is: Does the scenario in which the man has the pulley have a mechanical advantage over the...
  36. M

    Mechanical Advantage Question - Ropes

    I have to take an aptitude test that I have taken before and there are a couple questions that are stumping me. My first question I want to ask about deals with ropes / strings. It has an old-timey picture of a boy carrying books wrapped up in string and then attached to a stick and thrown...
  37. E

    Is PUSHING a wagon mechanical advantage?

    Hi all. So as we know the wheel can be a form of mechanical advantage. If I were to spin a wheel from its circumference and a rope was attached to its [smaller] axle, I would be applying less force per distance than is outputted on the axle. (I may have worded that funny but its not important...
  38. R

    Mechanical Advantage of a four bar linkage.

    I'm doing a project outside of school and I need some help with the mechanical advantage of a four bar linkage. Ideally I want to have a torsion spring attached to the frontward most arm so that I can load the linkage and have it fling forwards. I want to use a servo to load the spring which i...
  39. M

    Help Me Understand Mechanical Advantage Please

    ok, I know that being further away and using a fulcrum/pivot point from an object being moved takes less energy. i.e using a 4 foot crow bar to pry open something. But i can't grasp the concept of why being further away makes it so much easier. thanks
  40. W

    [Very Easy] Factors, Divisors and Mechanical Advantage

    Homework Statement The mechanical advantage of a lever is 0.08; force is not amplified, it is simply diminished; distance, however, is increased: Work input = Work output F x d = F x d F x d = 0.8F x ?(d) This must be a really basic question, but I'm compelled to ask as I'm somewhat...
  41. W

    Mechanical Advantage of a Lever

    Homework Statement If a lever has a mechanical advantage of 0.5 - does this mean the input force is not amplified but halved? Homework Equations The Attempt at a Solution
  42. W

    Finding Lever Lengths With Overall Mechanical Advantage

    Homework Statement If the mechanical advantage of a lever is, let's say, 10; the forces pushing down on the effort arm equate to 100kg and the forces pushing down on the load arm equate to 1000kg and the lever itself is 5 meters, how do we go about finding the individual arm lengths (i.e. the...
  43. M

    Mechanical advantage pickup truck crane

    I bought this truck crane for my dad. I want to calculate the mechanical advantage of it. http://www.harborfreight.com/1-2-half-ton-capacity-pickup-truck-crane-1647.html I know how to calculate the mechanical advantage of a hydraulic jack and of a lever but I am not sure about where...
  44. M

    Magnetic flow and mechanical advantage question

    Hi - I'm a layman with a problem I'd really appreciate some help with. I've been studying tattoo machines and have a question on magnetic flow and mechanical advantage. For background a tattoo machine is a essentially an electric horseshoe magnet with a bridge across the poles (doorbell...
  45. A

    Toggle Joint: Mechanical Advantage Explained

    Please explain in detail about toggle joint, especially about its mechanical advantage.
  46. G

    Does friction have a negative effect on the mechanical advantage

    does friction have a negative effect on the mechanical advatage of a pulley?
  47. N

    Mechanical advantage planetary gear help

    First of all, I am a newly registered user, so thanks for any help guys. I am confused with the concept of planetary gears. Let's say there is an rpm applied to a planetary gear of 600 rpm and the gear ratio is 3:1. So the output of the planetary gear then spins 1800 rpm (600 * 3). Now my...
  48. D

    Mechanical advantage, acceleration, work, power

    Basically i have no clue how to do this so I was hoping someone could help me on the formulas with some and explain/show how to set it up. Thanks :) 1. a block and tackle (a system of pulleys) with a mechanical advantage of 48 is used to life a piano 11 m to the third floor of a building...
  49. R

    Mechanical Advantage: Best Techniques & Solutions

    Dear Sirs/Mdms, There are many techniques to achieve Mechanical Advantage, for instance: using Gears, Pulleys, Belts, Levers, Hydraulics etc. I am not sure which gives the highest Mechanical Advantage (MA) in the most efficient manner , that is, to use the least components (eg. gears...
  50. P

    What is the formula for calculating mechanical advantage in a pulley system?

    http://www.getofftheinternet.net/pulley.png How would you go about calculating the mechanical advantage of this pulley system?
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