Lever Definition and 179 Threads

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



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{\displaystyle Load/Effort}

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  1. C

    Mastering Lever Mechanics for MCATs to Understanding Net Torques

    Hi guys. I haven't had physics in a couple of years and I'm trying to study for the MCATs. I've always had trouble with levers so I would really appreciate it if I could get some help. In particular, the following scenario confuses me: Say you have a man standing on a board, the fulcrum is to...
  2. A

    Constructing a Crank and Slotted Lever Mechanism in 3 Days

    hey i have got to make a scaled model of any mechanism that we see around(or maybe we don't sometimes) in the machine shop in under 3 days as our summer training project. we are provided with all the raw stuff and machines that one usually sees in machining shop. i have decided to make a crank...
  3. C

    How to Find the Velocity of Mass 9m at the Bottom?

    Homework Statement A lever of length 3L can rotate freely around a horizontal axis O. The end of each arm "2L" and "L" of the lever has one mass : "4m" and "9m" , respectively. Find the velocity of mass "9m" at the bottom. Consider that the lever was initially at rest in the horizontal...
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    Quick force on the fulcrum of a lever?

    Homework Statement I have a lever problem, i wish to find the force on the fulcrum; how do i determine this force? http://www.UploadYourImages.com" Fin = 80 N Fout= 21.5 N (yes, usually a lever is supposed to increase your power, but it represents a rowing oar)
  5. B

    Calculating Force on a Slightly Angled See Saw - Simple Lever Question Explained

    Hi, if you have a see saw with equal weights on each side, but it is at a slight angle; how do you calculate the force in Newtons on one side which is making it balance? Please see the picture: http://img408.imageshack.us/img408/6870/questionlw6.gif Thankyou
  6. A

    Solving Lever Calculations to Help Son

    My problem (trying to help an ay last keen son)-a lever 5m long, a weight of 300kg, a force of 100kg. The question says describe? I am trying to work out the distance from the end of lever to fulcrum or in other words where the fulcrum should lie. tried formula which has gone to...
  7. K

    Optimizing Lever Mechanics for Lifting Heavy Objects

    I can't figure this problem out and i don't know where to start. A young boy(50kg) wants to lift a boulder with a mass of 2500kg. He can wedge a board under it so that from the boulder to a pivot/fulcrum is 0.6 meters. How long does the other end of the board have to be for the boy to lift...
  8. C

    Forces on a hinged board used as a lever

    I'm having trouble with this one. Any help would be appreciated. A 3 m board of mass 4.5 kg is hinged at one end. A force F is applied vertically at the other end to lift a 75 kg block, which rests on the board 80 cm from the hinge, as shown in Figure 12-35. (b) Find the force exerted...
  9. T

    Designing a Bottle Cap Opening Device with Lever Mechanics

    Hi everyone, Im designing a new device for openeing bottle caps. But I am stuck, :cry: basically I have a second class lever (pivot at one end, effort at the other and weight in the middle). The weight is 72.21N the overall length from the effort to the fulcrum is 64mm and the length from the...
  10. T

    Designing a Bottle-Opener Lever: Finding Force-Material Conversion

    Hi everyone, Im designing a new device for openeing bottle caps. But I am stuck,:cry: basically I have a second class lever (pivot at one end, effort at the other and weight in the middle). The weight is 72.21N the overall length from the effort to the fulcrum is 64mm and the length from the...
  11. wolram

    What is the maximum weight a lever can lift based on its mechanics?

    If one is only considering the mechanics of a lever, what is the maximum a physically possible lever can lift ?
  12. G

    Push-up as Lever - How Much Weight Moved?

    I'm trying to determine approximately how much (percentage) of an athlete's body weight is moved when doing a push-up. I know it's a second class lever, but the lever itself is the load, and worse, the load is not evenly distributed along the length. I know approximate body segment weights, but...
  13. D

    Solving Farmer Lever Problem | Min Force Needed

    A farmer uses a lever to list a 210kg rock so he can remove it from the field. The distance, l1, from the lever's handle to the fulcrum is 9 times the distance, l2, from the fulcrum to the rock. Assume: the fulcrum is between the rock and the handle. the weight of the lever is negligible...
  14. S

    Understanding Levers to Mechanical Advantage and Force Distribution

    A lever 2 meters long is used to lift up a load of 1000 Newtons. The lever gives a mechanical advantage of 4. Sketch the lever and show the forces at each end of the lever and at the pivot point. Steer me in the right direction. What class of lever are we talking about?
  15. D

    Calculating Torque & Lever Arm for a Lunch Tray

    A lunch tray is being held in one hand. The mass of the tray itself is 0.201 kg, and its center of gravity is located at its geometrical center. On the tray is a 1.33 kg plate of food and a 0.285 kg cup of coffee. Assume lever arm of the thumb is 0.0620 m, lever arm of the finger is 0.113 m...
  16. B

    Ideal Mechanical Advantage of a Lever with 65N Force and 60/10 cm Arms

    A man uses 65 N to lift a box off the ground with a lever. The effort arm is 60 cm. The resistance arm is 10 cm. What is the Ideal Mechanical Advantage?
  17. B

    Solving Lever Mechanics: Find Ideal Mechanical Advantage

    Levers Please Help! A man uses 65 N to lift a box off the ground with a lever. The effort arm is 60 cm. The resistance arm is 10 cm. What is the Ideal Mechanical Advantage?
  18. B

    True Explanation of a Lever please.

    I have asked and I have asked, an no one has yet answered. I'm pleased to have discovered this free meeting place where I can ask so many educated people: how does a lever work? What's going on with the forces involved? I have read the typical formulas that are good at predicting the...
  19. P

    What is the pressure on the sample if 300 N is applied to the lever?

    A hydraulic press for compacting powdered samples has a large cylinder which is D1 = 13.0 cm in diameter, and a small cylinder with a diameter of D2 = 3.0 cm (Fig. 13-48). A lever is attached to the small cylinder as shown. The sample, which is placed on the large cylinder, has an area of 4.0...
  20. V

    How to Use a Lever to Lift a 1000 kg Car: Intro to Physics Problem

    I just started an intro to physics course this semester, and was given the following problem: You are driving alone one evening and come upon a car accident. A victim is pinned beneath the car, which weights 1000 kg. You are not strong enough to lift the car by yourself and, in a panic...
  21. 1

    Newton should have rediscovered the law of lever

    say i have a closed system of two weights in evacuated space on some distance between them. at the beginning they start the mutual attraction without initial push. conservation of impulse requires: d(p_1+p_2)=0 d(d(m_1x_1+m_2x_2)/dt)=0 if x_1=D_1 and x_2=-D_2 then you get the law of lever as...
  22. D

    Newton must respect the law of lever

    Newton must respect the law of lever as we all must. The law of lever is the 1st law ever in physics and every thing must agree with it. \documentclass{article} \begin{document} \section{Newton must respect the law of lever} \hspace{1 cm}I know most of you will object me as I'm the first...
  23. 1

    What is the true nature of the physics of the lever?

    I'm back again. My physics of the lever is better than any other. All of physics, even Newtonian mechanics stumble upon The Physics Of The LEVER!
  24. D

    Simulating a particle using the law of lever<-

    Simulating a particle using the law of lever<!-- I made a program in Delphi 7 entitled gods.exe and what it does is simulating a particle using no other but the law of lever. The particle is represented with a binary tree: DownLeft<-Top->DownRight. The two down's complete a lever in perfect...
  25. D

    The invisible lever in Archimedes’s gravity

    Say we have one weight floating in free space - vacuum and another weight in the same space on total distance D from the first. I’ll tell you the answer but any way my question for you is: “Is there a lever between the weights”? My answer is yes. Here is how I know it. First I have to find the...
  26. F

    Statics lever and valve question

    a lever is resting on a valve. the valve is located 3 in from the end of the lever. the total length of the lever is 9.5 in. a 4 lb force is present at the opposite end of the lever. the force makes a 28 deg angle with the lever. the lever makes a 20 deg angle with the horizontal. I am supposed...
  27. D

    Optimizing Lever Arm Length and Material for Maximum Distance in a Mousetrap Car

    am doing mine for distance should i have a long lever arm or a short lever arm, and how long should it be? and should i use a like a rubber string or just a normal one and how long should that be? thanks if you can reply by today
  28. P

    Right-angle lever paradox - Am. J. Phys.

    "Right-angle lever paradox" - Am. J. Phys. I'd like to read this article "Right-angle lever paradox," J. Charles Nickerson and Robert T. McAdory, Am. J. Phys. 43, 615 (1975) ---------------------------------------------------- Abstract: We present the problem of relativistic torques...
  29. D

    Finding Mass with a Lever: A Scientific Approach

    i was given a lab to find the mass of a meter stick using only a lever. Here's what the writeup says: Problem: Find the mass of a meter stick. (No cheaters, no scales!) Materials: Fulcrum, a 100 g mass, a mass hanger of mass 16.5 g, fulcrum pivot, meter stick. Procedure: You are...
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