What is Lever: Definition and 177 Discussions

A lever ( or US: ) is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge, or fulcrum. A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is divided into three types. Also, leverage is mechanical advantage gained in a system. It is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage. The ratio of the output force to the input force is the mechanical advantage of the lever. As such, the lever is a mechanical advantage device, trading off force against movement.The formula for mechanical advantage of a lever is




{\displaystyle Load/Effort}

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  1. Fury22

    B Lever balancing physics (video game design)

    Hi everyone! I am not a physicist or a physics student. Just a simple video game programmer. I have recently gotten into a discussion with my fellow programmer about a specific hypothetical problem regarding levers. The problem might seem very simple at first, but cause me a bit of headache...
  2. Big Tommy C

    Lifting a mass from a point that is offset from its center of gravity

    Good Evening Everyone. I am having trouble wrapping my head around the physics involved with the example below. At first i was looking at this as if lifting may create a lever of some sort, but I don't believe it has a fulcrum. I am trying to find a formula (if there is one) for lifting a mass...
  3. HighFlyer

    B Springboard physics questions for diving coach at YMCA

    I'm a diving coach at the local YMCA and I want to give a lesson regarding the physics of diving off the board with maximum efficiency. This is the type of diving board with an adjustable fulcrum, basically a lever with one end fixed with bolts. Its been almost 15 years since I've taken a...
  4. N

    Convert moment force at lever support

    I am trying to determine if a clamp holding a lever with a mass at one end can experience zero or reduced torque either by balancing the forces or converting the rotational torque into another form such as linear, I’ve looked at counterbalance with Steadicams etc. but I believe this just...
  5. L

    How long would a lever have to be to compete with a hydroelectric dam?

    How long would a lever have to be for the weight on the effort arm to generate the equivalent energy of a single hydroelectric dam generator? State weight/force in kg. My ponderings: The weight could be anything, would be interesting to use water weight from a passive air water condenser in a...
  6. F

    How a force is amplified in a lever from the standpoint of internal stresses?

    Hello, While trying to understand how a lever truly works and a force can be amplified using a larger lever arm, I read a thread on how levers amplify forces (https://physics.stackexchange.com/questions/22944/how-do-levers-amplify-forces ) and the discussion involves stresses, internal torques...
  7. L

    Determine the velocity of two balls after the first collides with a lever

    In the figure below Ball 2(B2) is hanging and attached to a square lever. B1 drop from gravity and hit the lever as shown. Calculate velocity of B1 and B2 with gravity influence right after collision. The mass of B1 and B2 is identical. Using energy equation E1=E2, therefore VB2 final = VB1...
  8. MattGeo

    Torque and Moment of Inertia of a Lever Arm

    I never really considered this back when I was taking physics in college but imagine for the sake of thought experiment that you have an extremely and impractically long wrench and it is fixed to the bolt you wish to tighten. Now the longer the lever arm the greater the torque so if you double...
  9. J

    Air Cylinder connected to a Lever that drives a Pulley for Applying Belt Tension

    Hi, I am looking for some guidance on how to approach this calculation. I have an air cylinder operating a lever assembly that then applies pressure to a pulley of which a belt is wrapped around. I need the belt to have about 4500 lbs of tension. How do I work backwards to figure the required...
  10. A

    Discover the Secret to Effortless Motorbike Lifting with Central Stands

    Homework Statement:: How does the central stand of this guy's motorbike enable him to lift it with little effort? https://youtu.be/QjhqcrGvlvg Relevant Equations:: I understand he succeeds by using mechanical advantage having good leverage from the engineering in the stand. Could anyone help...
  11. M

    Finding the Torque of a shaft that is spun by a lever

    Homework Statement: Hi there. I am new to this forum, but I joined just to ask some input from anyone who may be kind to help. I have this attached file where you can see all the values and equations I have used but there is one bit where I need help. finding Torque on Shaft B, I appreciate...
  12. R

    Would a longer lever require less force to hand pump water? (PHOTO)

    I think that it would take less force to pump water based on the lever principle. But I'm not so sure! Here's a drawn photo.
  13. A

    Compound lever arm - compressor design

    So what comes to mind is utilising the full height and further node points in a triangulated system... however being only just now introduced to the concept of a compound lever I am unsure of how to get this system to work. Any thoughts much appreciated.
  14. Aleoa

    Deriving the lever law using infinitesimals

    I'm trying to derive the lever law by myself, however, I'm stuck. Please follow the logic of my calculations. Every object in the picture has the same mass. I want to prove that, under the effect of the gravitational force, I can replace the objects in A and C with the two objects in B, and...
  15. H

    Luffing Jib Load, With and Without Sheave Pulley

    Now I am working with a DIY Luffing Jib Crane. Mys subcon said that: Tension of red rope for hanging a blue box load at the tip of the boom i(A) s as the same as hanging it with pulley and tied to the motor/ground_B (System in a Static Load Condition).. Blue Rope and Pulley weights are...
  16. T

    Force applied to lever arm to twist foot pound torque

    If i need 1000 foot pound torque of 1000 foot pounds twisted very easily How long should the lever arm be and and how much force at the end of lever arm is required ? Tony Singh
  17. TymerTopCat

    1st class lever question (I think) -- tilting antenna erection mechanism

    I want to build a tilting wireless internet structure that is 24 feet high, with a fulcrum at 6ft. The idea is when I want to work on the device (which is 24 ft in the air), I can just unlatch the mast and tilt the structure down and work on it. I would like to have the pivot (or fulcum) at six...
  18. J

    Calculating Effort Needed for Unevenly-Loaded Class 2 Lever

    Hi, I essentially have a class 2 lever, which holds an unevenly spread load. The lever itself (platform) is however an even weight throughout its length (except for the odd RSJ I've welded in for strength). This is an OLD machine, and hence we're going to build a bigger, stronger and higher...
  19. Bayu

    Simple lever for a 3d printed gate

    Homework Statement Hi I am new here!,i want to thanks for all great information, Today i try to make a lever works with my hot wheels start gate,it should be work like gate,when i push the lever down,the gate will going down but i can't make the gate open at the same time between the first...
  20. R

    Calculating torque at a distance from the lever

    Hi there, I am an engineering student studying my masters, but have run into a roadblock in my calculations. I know I'm missing something obvious but i just can't see it. Too close to the woods and all that! Anyway, i have the rear end of a motorcycle. to calculatew the overall moments, i have...
  21. J

    Class 3 Lever: Non-perpendicular Effort

    Hi, We have a machine in our workshop in which we are modifying to relieve the amount of lifting force required by the hydraulic ram. This will subsequently reduce hydraulic system pressure which is the main goal. I'm trying to calculate the current configuration. It consists of a class 3...
  22. I

    What is the force generated by a lever in a closed position?

    So.. I'm trying to figure out if a design Idea has any potential. The figure below shows a lever mechanism operated by a rack and pinion gear assembly. I've calculated the torque in the pinion to be 252 Nm. What will be the force at the contact pad, generated by the lever when in the closed...
  23. M

    Effect of load and load distance on peak and avg power

    I am trying to create a lever which has mass on one end and i need to lift the lever. A picture showing the lever setup is in this link: https://imgur.com/WeH4oK7 The system is like seesaw ( from -20 degrees to +20 degrees at constant angular velocity for time period 't') The input angular...
  24. 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...
  25. 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...
  26. 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...
  27. G

    Law of the lever without (infinitesimal) displacements

    Hi. Usually the law of the lever or similar force laws for simple machines are derived using $$W_1=F_1\cdot s_1=F_2\cdot s_2=W_2\enspace,$$ sometimes called "Golden Rule of Mechanics". However, these force laws also hold in the static case where no work is done. Is it possible to derive the law...
  28. ISamson

    Faster than light: Instantaneous lever

    Hello. I have been thinking on faster than light things. I thought about: chemical engines, lasers, wormholes... All that kind of cool, advanced physics. But, I stumbled on faster than light mechanical actions. I thought about a lever: first class, if you wish, if you apply a force to one side...
  29. S

    Compound lever on a mousetrap vehicle?

    Hello, I'm trying to make my mousetrap car go very fast. I saw this on youtube . Does this provide any advantage to make it go faster? How would you implement a compound lever to a mousetrap car?
  30. J

    Lever, bar, and mechanics why does this happen?

    two saipens one known as Alpha who is on the left and the other on right Beta are present, Alpha first presses down on a bar and Beta has to use all of its strength to lift Alpha's hand a distance h a distance, in this scenario the fulcrum is placed close to Beta, now in the next scenario it is...
  31. B

    Automotive How does a weight distributing hitch help towing capacity?

    Most hitches are rated as "X, 0.1*X weight-bearing, Y, 0.1*Y weight-distributing" where Y > X and the first number is trailer weight, second number is tongue weight. It has been described to me many times that the weight distributing hitch (with 'stabilizing/leveling' bars) "takes weight off...
  32. M

    Balancing Lever Problem: How Many Rings on Each Side?

    Homework Statement The problem: a) The first photo (slika 1) displays a swing in balance, on which are put on two rings. and an unknown object. How many rings need to be replaced on the right side, on the place of the unknown object, so the swing will stay in balance. b) How many rings have to...
  33. H

    The force required to raise a bridge/lever to an angle?

    Homework Statement Tower bridge in London is an example of a bascule bridge (moveable bridge) where each part that is raised up is called a ‘span’. In this photo, the two spans are raised to an angle of 38° to let two tug boats through. Each span is 30.5 m long and weighs 1 x 108 kg (you can...
  34. S

    Rotational Motion Question, lever arm with two masses

    Homework Statement [/B] A uniform rigid rod with mass Mr = 2.7 kg, length L = 3.1 m rotates in the vertical xy plane about a frictionless pivot through its center. Two point-like particles m1 and m2, with masses m1 = 6.7 kg and m2 = 1.6 kg, are attached at the ends of the rod. What is the...
  35. Vagulus

    Force exerted by hand on a lever

    Is there a generally accepted ball-park figure for the force a human can apply to a lever? Obviously, I am not thinking of an Olympic weight-lifter or of my three-year-old granddaughter - just the turning moment generated by the 'average' person standing up and pulling/pushing on an horizontal...
  36. B

    Torque produced in lever setup

    Hi guys, It's been a while since I've done much resolving forces stuff, and I'm struggling to make sure what I'm doing is right. I have a setup like below, and I want to find the torque around point D due to the force acting at point A. I've had a couple attempts but I feel like I'm just...
  37. B

    Torque around a point from lever linkage

    Hi all. Brushing up on some of my force and torque stuff so I can do some modelling in software. Homework Statement I have a system as shown in the picture. A force F acts at point A, which is the end point of the lever AB. Connected to the lever is a link BC, and connected to BC at point C is...
  38. R

    Calculating mass of the horizontal leg of a L shaped lever

    Hey everyone, been stuck on this for over a day now, wondering if anyone is able to tell me if I am on the right track. 1. Homework Statement "In your calculations for M1 (bell crank lever), note that the mass of the horizontal leg is contributing to the anti-clockwise moment. Given the masses...
  39. D

    Offset Torque: Solving the 1000N Problem

    Hello guys, I am doing some basic design work and can't remember how offset torques work. I am doing the sum of the torques should be equal to 0 in order to find the tipping point around either of the wheels. My problem is with the 1000N applied at to top taking the pivot point around the...
  40. Dante Meira

    Does the weight of a lever influences the amplification?

    According to Wikipedia: Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Ideally, the device preserves the input power and simply trades off forces against movement to obtain a desired amplification in the output force...
  41. B

    Starting force of a falling object on a compound lever

    Hello, I am building a bicycle with suspension on it. The rear wheel is connected to the bike via an axle on a swing arm (a long lever), connected to a linkage lever which is connected to a shock, which has a spring on it. Ultimately I'm trying to calculate the force applied to the shock...
  42. N

    Create Home Brew Bottle Capper: 6 at a Time

    So I've been working on a home project of creating a movable, self contained, ergonomic beer small (3-6 GA) home brew kit. I'd like to be able to fill and cap 6 bottles at one time. I'm working on a prototype for the filling process but need some ideas for how I could apply 6 caps to six bottles...
  43. P

    Calculating the dimensions of a lever and a column

    Hi, I have a system with a lever arm that's attached to a vertical support at its pivot point. The lever is pushed up by hand and is supported by a stay lid like in the image. I need to calculate the area and thickness of the arm and the column but the only numbers I have is the load attached...
  44. C

    Maximum Torque / Evenly Spread across a lever.

    Homework Statement The maximum torque on a lever is 1.5 x 10^6 Newtons. How many people of weight 750N can stand evenly spaced on this lever, which has a length of 20 meters? Homework Equations T=FR Weight=mg W=Fd X = Number of people The Attempt at a Solution I have set 1.5x10^6 N =...
  45. john101

    How to Calculate Pressure Exerted by C in a Lever and Fulcrum Configuration?

    as B moves to over A, ( A is a fixed point ) C slides up its guide slot and is stopped by a non compressible object and no amount of force can shift it further up. measurements in units. At this point >> how do I know how much pressure C excerts upwards. psi? Mpa? I hope I'm making myself...
  46. M

    A gyroscope as weight for a lever

    if i got a beam of 40 meters and one side (35m) is 12 metric ton how do i calculate the forces on the gyroscope. I tried to caclutate it but i just get a torque and a angular momentum, how do i converted torque and angelur momenten in Netwons?
  47. euphorik

    Help me move a floating bridge 90 degrees w/o getting wet

    Hello! I was hoping someone here could help me solve a real world problem. So my university pool has something called a bulkhead, which is basically a bridge that floats above the water so that people can walk across the shorter dimension of the rectangular pool (50 meters long, 25 yards wide)...