What is Lift: Definition and 613 Discussions

A surface lift is a means of cable transport for snow sports in which skiers and snowboarders remain on the ground as they are pulled uphill. While they were once prevalent, they have been overtaken in popularity by higher-capacity and higher-comfort aerial lifts, such as chairlifts and gondola lifts. Today, surface lifts are most often found on beginner slopes, small ski areas, and peripheral slopes. They are also often utilized to access glacier ski slopes because their supports can be anchored in glacier ice due to the lower forces and realigned due to glacier movement.
Surface lifts have some disadvantages compared to aerial lifts: they require more passenger skill and may be difficult for some beginners and children; sometimes they lack a suitable route back to the piste; the snow surface must be continuous; they can get in the way of skiable terrain; they are relatively slow in speed and have lower capacity.
Surface lifts have some advantages over aerial lifts: they can be exited before the lift reaches the top, they can often continue operating in wind conditions too strong for a chairlift; they require less maintenance and are much less expensive to install and operate.

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  1. A

    Calculation of coefficient of lift using a wind tunnel

    I have done a lab experiment, to determine the coefficient of lift for an aerofoil, keeping the angle of attack constant. The equation I have used is Lift= (1/2) v times v times A times ρ times Coefficient of lLift v= Velocity of air ρ=air density A= planform area to give...
  2. A

    Work required to lift object from earth's surface to circular orbit

    Homework Statement How much work must be done by a rocket engine to lift a 1000kg payload from rest on the Earth's surface to a circular orbit of radius 2Re (2 times the radius of the earth)? Homework Equations Eg = -GmM/r Ek = GmM/2r The Attempt at a Solution I know ΔE = W I...
  3. A

    Take-off Lift coefficient for the A380 or other very long range airliners?

    Does anyone know what the take off life coefficient for very-long range airliners might be in general or where i could find this kind of information? I'm doing some calculations on things like aspect ratio, landing lift coefficient etc for a report on aircraft design. My results are...
  4. J

    Air Lift in Water: How Much Does it Lift?

    Hi, One cubic foot of air will lift approx 64 lbs in water (basically). So if you start at a xxx depth with a balloon that is one cf, as it rises and expands the lift capability increases, right? What if the container was an aluminum sphere. Actually, say you have 2 same size spheres, both...
  5. D

    2-axis rotation to 3-axis lift

    Homework Statement Hi there, In my experiment I have a disc which needs to be pitched and rolled about it's centre. The disk is mounted by three verticle "pistons" one every 120degrees. I need to convert a tilt in the x-direction \theta_x and a tilt in the y-direction \theta_y to how much each...
  6. X

    Pitching moment and lift coefficient

    Consider a proposed airplane design shape in a wind tunnel. The forces and moments are measured at the proposed center of gravity location. At zero angle of attack, pitching moment is zero and lift is 10N. At 5 degrees angle of attack, pitching moment is -5Nm and lift is 60N. The chord of the...
  7. I

    Average power needed to lift an object

    Homework Statement A weightlifter raises a 115kg weight from the ground to a height of 1.95m in 1.25 seconds. What is the average power of this maneuver. Homework Equations m = 115kg Change in Y = 1.95m time = 1.25 seconds The Attempt at a Solution V = 1.95/1.25 = 1.56 m/s a...
  8. T

    Lift from airfoils, decrease lift as a result of curved shape at large angles?

    Hi, in my point of view lift is created as a result of two pressures, the static and the dynamic. The dynamic pressure is the dominating creator of lift at large angles of attack. For example a flat plane at 45 degrees will create lift. The static pressure is the dominating creator of...
  9. E

    Calculating Power Requirements for a Ski Lift

    Homework Statement A ski tow operates on a slope of angle 14.3 of length 350m . The rope moves at a speed of 12.1km/h and provides power for 49 riders at one time, with an average mass per rider of 75.0kg Estimate the power required. to operate the tow.Homework Equations W=mgh P=W/T...
  10. B

    How Does Hovercraft Technology Aid in Heavy Lifting?

    I work in a hospital, and recently we acquired a device by which air flow from a small low-pressure pump is fed into an inflatable mattress with many tiny holes on the bottom side. As this mattress inflates, it creates a cushion of air beneath it, capable of lifting a 1,000 lb person so that...
  11. L

    Calculating Force P Needed to Lift 150kg Cylinder

    I've tried a whole manner of different things to try and solve this: Determine the smallest force P needed to lift this 150kg cylinder. Coefficients of static friction At A: 0.7 At B: 0.3 At C: 0.4 I've tried different things and I'm lost on how to solve it.
  12. K

    Can a lift electromagnet pull a permanent magnet?

    A lift electromagnet has N + S pole on the same side. will it push or pull a permanent magnet which has N & S pole on opposite side? If I have a lift electromagnet and a permanent magnet, both can pull 100 lbs. What is the break away force if I put them together? Thanks
  13. A

    Thrust to weight ratio and lift

    hello a plane would need a thrust to weight ratio of 1 of fly straight up without losing speed but how can a plane in level flight maintain its altitude with <1 TWR since to maintain a level flight you need to have lift = weight so your engine needs to supply enough power to generate...
  14. C

    Lift Curve slope of wing , tail fin

    Homework Statement Hi Guys, Its great to be on this forum, some of the posts here have been really useful for me . Anyway, I am trying to calculate the lift curve slopes of an aircraft wing, tail and fin. (3D wing) The only data I have are the various quarter chord sweep angles, Aspect...
  15. B

    How much charge on a plate needed to lift it against gravity?

    Homework Statement A thin uniform metal disk lies on an infinite conducting plane. A uniform gravitational field is oriented normal to the plane. Initially the disk and plane are uncharged; charge is slowly added. The mass of the disk is M, and its area is A. What value of charge density is...
  16. S

    Creating Vertical Lift with Industrial Magnets: A Possibility?

    I have been thinking about this for some time and I came up with this.Very very strong industrial magnets will be used for lift and thrust.Every part of the craft will be attached together. No. 1 and 2 magnets will be used for vertical lift.No. 1 magnet is set at its position and can't...
  17. V

    Why do maximum L/D and max. lift not occur at the same angle of attack?

    Hello, I did a wind tunnel test with a NACA 0012 airfoil. And my results showed that the highest lift-to-drag ratio occurred at an angle of 12degrees where as my maximum lift is at 15degrees. I even read somewhere that these values do differ but there was no such explanation as in why is that...
  18. C

    An flying object needs lift,but this lift is like buoyant force in air?

    An flying object needs lift,but this lift is like buoyant force in air?? just like when any object is immersed in water it feels lighter because a net upward force is acting on it same way do net upward force is acted by air when any object is flying in air?? and that net upward force is more...
  19. N

    Calculating Forces on Scissors Lift Arms

    Homework Statement I need help in calculating the forces that act upon the arms of a scissors lift. Attached is the force diagramm and some calculations i made earlier. The calculation was made based on each arm It would be nice if any of you could have a look and check whether the...
  20. C

    Lift and Drag formulas on a plane

    I am going to make a R.C. airplane and need help understanding the physics behind it. I have found these formulas for lift and drag. Lift=Cl*(r*V^2)/2*A Cl=2*pi*AoA Drag=Cd*(r*V^2)/2*A Cd=Cd0+Cl^2/(pi*A*R*e) Now I have two questions. First, are these the correct formulas for finding...
  21. B

    Calculating Car Lift Height with a Hydraulic Lift

    Homework Statement A hydraulic lift is used to jack a 970 kg car .12m off the floor. The diameter of the output piston is .18 m, and the input force is 270 N. If the input piston moves .13 m in each stroke, how high does the car move up for each stroke? 2-3. Relevant equations and attempt at...
  22. U

    What power is needed to lift the water to the surface?

    An electric pump pulls water at a rate of 0.25 m /s from a well that is 25 m deep. The water leaves the pump at a speed of 8.5 m/s. 1. What power is needed to lift the water to the surface? 2.The necessary increase in power the pump to make the water flowing through it quickly 8.5m/s my...
  23. S

    Exploring the Possibility of Car Lift Through Airflow

    When air flows over an airfoil, the air flows at the top flow faster than the bottom and hence creates a net pressure difference, and thus an upward force is applied on the wing. Thus the airplane lift from the ground and keep flying in the air. Now, imagine the side view of a car. Car...
  24. R

    Length of bar needed to lift a crate(Torque, static equilibrium problem)

    Homework Statement A large crate weighing 4520 N rests on four 12-cm-high blocks on a horizontal surface (figure below). The crate is 2.0 m long, 1.2 m high, and 1.2 m deep. You are asked to lift one end of the crate using a long steel pry bar. The fulcrum on the pry bar is 11 cm from the end...
  25. F

    Helicopter Rotor Lift Equation

    Hello! I am creating, or at least attempting to create, a human-powered helicopter. I need an equation to figure out the lift from the rotors. I plan to use four counter-rotating rotors, three blades each, and each blade made of foam, with aluminum ribbing. The blades will be six feet each...
  26. I

    Airfoil lift in superfluid flow

    A superfluid has zero viscosity. Lift of an airfoil (and any shape for that matter) is zero without fluid viscosity. So, superfluids shouldn't generate lift when flowing around an airfoil. Is that true? I think it is impossible for a superfluid not to generate lift on an airfoil, because...
  27. C

    How can the lift equation be derived using Bernoulli's law?

    Hi there. I am trying to derive the lift equation for aircrafts through Bernoullis law. I am having some trouble though, since I wind up with the differences between the force that acts on the top of the wing and the force that acts under the wing instead of the net force, so to speak. Could...
  28. M

    Fan design to improve lift force

    Homework Statement Can the addition of a second set of fan blades, below the first set and on the same axis, improve the lift force created? What is the theory associated with this phenomena? Homework Equations none, practical application in lab setting. The Attempt at a Solution...
  29. T

    Calculate Force to Lift Weight in Multi-Scissor Lifts

    Hello, I am building a scissor lift for a design project. I located a formula for calculating the amount of force required to lift a weight as given: F=(W+(Wa/2))/(tan(theta)) Where F is the amount of force required, W is the weight of the payload and the load platform, Wa is the weight of...
  30. R

    Weather Ballon with Camera/GPS payload. 1x600g or 2x600g balloon for lift?

    Hi I am starting a project and will be inflating a 900g Kaymount weather balloon with a payload that consists of a styrofoam box inside of that will be a SPOT personal gps tracker, Camera and a Flip HD camcorder. I purchased 2 of the 600g balloons. I will do this by filling one up and attatching...
  31. S

    Which is the airfoil having highest lift to drag ratio?

    I working on a new airfoil design. Please tell me the airfoil having highest lift to drag ratio, I need it for comparison.
  32. F

    Rigging - Single Hook 4-Point Lift

    I am lifting a rectangular structure, all lift points on the same elevation. However, the 4 lift points are not evenly distributed around the CoG AND we have an intended 10 degree tilt on the structure being lifted to facilitate installation. I have attached a spreadsheet/dwg in PDF This...
  33. E

    Electric power for lift and torque

    One tonne dead-weight is to be lifted in the air and moved horizontally by means of a propeller activated by electric motor. Questions: (1) What is the electric power (components U, I) sufficient and necessary for the task? (2) If, instead of (1), the generated electric field is used to...
  34. S

    Finding tension in a cable of a accelerating lift

    A lift has mass 800 kg. It is moving upwards and has an accerleration of -0.1 ms-2. The lift is supported by a single cable. What is the tension in the cable? I get T = -7760 N (I'm taking up as negative), just checking what anybody else gets F = ma T + mg = -(-0.1)m T = 800(0.1...
  35. K

    How can I calculate the lift of a helium balloon?

    Say I want to send a helium balloon into the sky. For all intents and purposes this balloon is circular, with volume V. I will fill it with helium to the same pressure as the air outside it (I assume that this is important). The weight of the balloon and the payload is W. So, I assume I have...
  36. G

    Find torque to lift 100kg F=Ma

    Hi all, Please note this is not a home work. Working on a NPD.Please look at the jpeg file I have done few basic calculations to find torque to lift 100kg F=Ma F=100x9.81 F=981N Torque=Force x Distance T=981x.77 T=755Nm The torque on the gearbox output shaft required to lift is...
  37. O

    AA battery to lift 1000kg up 1meter

    I am on the Earth's surface and I want to lift my 1000kg rock up 1m. I quickly calculate the amount of work required to accomplish this feat: 1000kg * 9.81 m/s2 * 1m = 9800 kg m2/s2 or 9800 joules thats really not that much work. i see from...
  38. M

    Calculating the force required to lift tilting mass (similar to dumptruck)

    Homework Statement Hi I am very keen to solve this problem, it is not for coursework, just something I am interested in designing. I have attached a sketch I drew using my index finger on my laptop :) I would like to determine the Force required of a cylinder to Lift...
  39. Faradave

    Can Orthosonic Lift Challenge Traditional Theories of Flight?

    As I have been banned 3 times from PF for "continued promotion of personal theory", I am hesitant to begin this thread which, as far as I know, is entirely personal theory. So, let me start with a disclaimer. I am not an engineer, just an amateur experimenter, fascinated by physics. All of...
  40. M

    Can Someone Help an Old Timer whom would like to Lift his Communications Tower?

    I am getting a bit older, and I have a Aluminum Communications Tower, and used to angle it up by myself from the back of the house to the side. Now I would like to lift the tower to its vertical position on the side of the house using the existing aluminum angled bracket plasma welded to a...
  41. A

    Estimating the Number of Balloons Needed to Lift You Off the Ground

    Homework Statement To an order of magnitude, how many helium-filled toy balloons would be required to lift you off the ground? Helium is an irreplaceable resource so develop a theoretical answer rather than an experimental one. Homework Equations ? The Attempt at a Solution...
  42. D

    Calculating Force Needed to Lift 79kg Mass at Const. Speed

    A woman raises herself in a bucket. How hard must she pull downward to raise herself slowly at constant speed? The mass of the person plus the bucket is 79 kg. m=79kg g=9.8m/s^2 (downward) i know \SigmaF=ma so i end up with 774.2 N. I'm a little lost as where to go now.
  43. T

    How much lift thrust would a 252 CFM 120mm fan provide?

    Hey guys, I'm a college student looking to build a miniature RC plane based off this picture here: [PLAIN]http://www.kruxor.com/wp-content/uploads/2010/07/SC2_Banshee_Art.jpg As you can see, the thrust needed to lift and mobilize the plane is provided by the two fans on the sides (does this...
  44. S

    Lift via accelerating static air gas particles down?

    I’ve been reading about airfoil lift and have found it rather difficult to find an answer to this question. Is the lift generated by an airfoil primarily dependent on accelerating static air gas particles down?
  45. U

    Can You Calculate Lift Force for a RC Quad Rotor Helicopter?

    Hello! I'm planning to start a project to design a RC controlled quad rotor helicopter. If it works out well I have an idea of making it autonomous. So first thing is that I want to know how to calculate the lift force from a single motor ?
  46. W

    Connection, horizontal lift, and berry phase

    i am now reading the PRL paper by simon on berry phase under adiabatic approximation, the wave function evolves as \langle \psi | d/dt | \psi \rangle=0. how to relate this equation to the connection on a fiber bundle? how to understand that the wave function is parallel transported?
  47. N

    Calc II word problem(work needed to lift a leaky bucket)

    Homework Statement From Stewart Calculus Concepts and Contexts 4th edition pg.473 section 6.6 #15... :A leaky 10-kg bucket is lifted from the ground to a height of 12 meters at a constant speed with a rope that weighs 0.8kg/m. Initially the bucket contains 36kg of water but the water...
  48. M

    Calculating Forces & Heights in a Hydraulic Lift

    Homework Statement In a hydraulic lift the radii of the pistons are 1.75cm and 10.5cm. A car weighing 18.5kN is to be lifted by the force of the large piston. a.) what force must be applied to the small piston? b.) when the small piston is pushed 1.00cm, how far is the car lifted? c.) find...
  49. M

    What's the energy source for capillarity to lift liquid up?

    I just recently had a conversation, where we discussed if liquid is getting colder as it moves along thin tube where it "normally" wouldn't. And if it does, doesn't it mean we have a system that makes things colder without warming anything around it? Which I thought wasn't possible.
  50. E

    Weight of man in a lift when lift is ascending/descending.

    I guess this is really basic physics to all of you but it got me thinking abit. Homework Statement A man of mass 72kg tries to weigh himself in the lift using a weighing machine I am required to find his weight when the lift is stationary ,accelerating upwards(3m/s^2),travelling upwards at a...
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