Lift Definition and 614 Threads

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. D

    Hydraulic Lift.( U tube) and oil

    Homework Statement A 12,000 N car is raised using a hydraulic lift, which consist of a U - tube with arm of unequal areas, filled with oil with a density of 800 kg/m^3 and capped at both ends with tight-fitting pistons. The wider arm of the U tube had a radius of 18. cm and the narrower arm...
  2. A

    Exploring the Physics of a Hobby: Investigating Lift in Vacuum Chambers

    I am interested in this Hobby. I have seen several experiments and it looks pretty easy to do. I am wondering what exactly lifts this? Is it Ions or ?? They had done a test in a vacuum chamber and it was still working, are ions present in a vacume? If it's not ions, then what makes the...
  3. M

    Balancing a Hydraulic Lift with Two Pistons

    Homework Statement A hydraulic lift has two connected pistons with cross-sectional areas 5 cm2 and 550 cm2. It is filled with oil of density 520 kg/m3. a) What mass must be placed on the small piston to support a car of mass 1500 kg at equal fluid levels? this was no prob. =13.61...
  4. M

    Calculating Mass to Support Car Weight on Hydraulic Lift

    Homework Statement A hydraulic lift has two connected pistons with cross-sectional areas 5 cm^2 and 550 cm^2. It is filled with oil of density 520 kg/m3. a) What mass must be placed on the small piston to support a car of mass 1500 kg at equal fluid levels? Homework Equations...
  5. N

    Calculating the Wind Speed Needed for a Weightless Building on Titan

    I think this is a pretty simple question but I can't seem to figure it out: If there is a 90,000 kg building (20 m deep, 10 m long, and 10 m wide) on the surface of Saturns moon, Titan, how fast does wind have to blow over the top to have the structure become "weightless" (the air below the...
  6. C

    Understanding Airfoil Wingtip Effects on Lift & Drag

    When an air passes over the wingtip of the airfoil, the upwash created at the leading edge 'reduces' the Angle of Attack, thus reducing lift. So why does this affect increase induced drag. The way I understand it, the greater the AoA (more lift), the more induced drag that is generated. Help...
  7. B

    Understanding Lift Generation and Investigating Results

    I've just finished the practical part of an investigation into lift and angle of attack. I also took airspeed readings over the top and bottom of the wing at the leading and trailing edges. What I'm having trouble with is grasping how lift is generated. I understand the underlying principles...
  8. M

    Calculating Tension Needed to Lift 1400 kg Car

    Homework Statement How much tension must a rope withstand if it is used to accelerate a 1400 kg car vertically upward at 0.50 m/s2? Homework Equations Fg=mg F=ma The Attempt at a Solution So far i know Fg=13720 and the Fnet is 700 so I'm not sure but do i subtract 700 from 13720?
  9. B

    Find the Min. Balloon Diam. for a 269kg Lift

    Homework Statement Under standard conditions, the density of air is 1.293 kg/m3 and that of helium is 0.178 kg/m3. A spherical helium balloon lifts a basket plus cargo of mass 269.0 kg. What must be the minimum diameter of the spherical balloon? Homework Equations p = F/A The...
  10. J

    Can a Human Fly? Calculating Wave Speed to Lift 75kg Weight

    Ok, propably everyone here knows that IN THEORY it is possible for a human to fly. This question has been bugging me a lot and I know it can be solved using some kind of aerial physics (Dont know the term :D). Therefore my question is: How fast must 75 kilograms weighing human wave his hands...
  11. J

    What force must be applied to lift the load?

    Homework Statement A rod is being used as a lever as shown. The fulcrum is 1.2 m from the load and 2.4 m from the applied force. If the load has a mass of 11.6 kg, what force must be applied to lift the load? ____ N Homework Equations ? The Attempt at a Solution When doing...
  12. B

    How Does a Delta Wing Create Lift?

    I understand how an ordinary wing works but I cannot find anything on how a delta wing works, the only thing I know is that it creates vortices on the upper wing surface, but how do these vortices create lift?
  13. H

    Solving a Puzzling Lift Problem: Net Upward Force on the Man

    Homework Statement Hey everyone, this problem has been bugging me for days now, and no matter how many times I've attempted it, I feel like its going wrong. http://img258.echo.cx/img258/4409/lift3ad.png The buillder has a mass of 75kg and the cradle has a mass of 35kg. The builder...
  14. J

    Estimating Lift from a NACA 0012 Airfoil

    Homework Statement I have recorded raw pressures for from a wind tunnel for a NACA 0012 airfoil with 30 surface pressure taps. I have computed Reynolds Number for 3 angles of attack. I have computed the Pressure Coeff. for each pressure and graphed them verses the non-dimensionalized...
  15. P

    More Work Required for 4kg Lift than 1kg Push

    Is More work is done to lift a 4.00-kg object a distance of 1.00 m at a constant velocity than to push a 1.00-kg block a distance of 1.00 m with a force of 39.2 N? I can find the work done in the 2nd case using W=fd= 39.2 J.
  16. C

    Calculating Lift Force of Helicopter Propellers

    Homework Statement A 5400 kg helicopter accelerates upward at 2.17 m/s2. The acceleration due to gravity is 9.8 m/s2. What life force is exerted by the air on the propellers? Answer in N. Homework Equations Fnet=ma The Attempt at a Solution I am making the acceleration positive...
  17. I

    Vertical lift aircraft fuel longevity

    Anyone know how long a typical let's say news helicopter can last in the air given how much fuel it holds? I am not sure but I heard a news helicopter or a police helicopter probably won't last more than 3 hours in the air. Some military transport helicopters can only do about 2 and attack...
  18. A

    Solving Hydraulic Lift & Friction Force Problems

    Homework Statement 1) Consider the hydraulic lift which has a smaller piston of area A1 and a larger piston area A2. Initially the two pistons are not moving. Show that in order to raise the larger piston by a distance d2, it is necessary to apply a force △F = ρg(A1 + A2)d2 on a smaller...
  19. T

    Does Balloon Lift Force Increase or Decrease with Altitude?

    As a helium balloon increases in altitude, the density of the air inside decreases. However, the density of the air surrounding it (The atmosphere) also decreases with altitude p=p0*exp(-z/z0), where z0 is the scale height of the atmosphere. So does this mean the lift force acting on the...
  20. R

    Dry Lift Testing: Resources for Turboshaft Fuel Pumps

    Can anyone point in the direction of any information on dry lift testing for turboshaft fuel pumps? I need to write a good practices guideline for this and need to find as much info as I can. Thanks.
  21. T

    If Zeus can do anything can he make a stone he cannot lift?

    I came accros this question while reading a bit of Logic and i was wondering what you guys think about. If Zeus can do anything can he make a stone he cannot lift? Hope its not too trivial. thanks
  22. J

    Coefficient of lift formula

    Hi, i have to find a formula for the coefficient of lift that has the angle of attack and wing shape (airfoil shape) in it. Also, where can i find airfoil shapes for different planes? Thanks
  23. K

    Acceleration of object in a moving lift

    A small body is released so that it falls to the floor of a lift moving downwards at a constant velocity. How would the acceleration of the body as observed by someone in the lift compared with that observed by a person stationary with respevt to the lift shaft?
  24. K

    Solve Pulley System Problem: Lift 52 kg Desk 2.32 m with 620 N

    Homework Statement A pulley system has an efficiency of 76.9%. The acceleration of gravity is 9.81 m/s^2. How much of the rope must be pulled in if a force of 620 N is needed to lift a 52 kg desk 2.32 m? Homework Equations Force = ma Work = force * distance The Attempt at a...
  25. T

    How to lift water out of a pool

    Homework Statement given, diameter and height of pool, depth of water, density of water and gravitational acceleration. g = 9.8 height is 4m 2r = 20m depth of water = 3.5m density =1000kg/m^3 So, I'm supposed to find how much work is needed in joules to lift the water out of the pool...
  26. P

    How to calculate lift for delta wing

    is the formula below valid to calculate the lift coefficient for a delta wing? Cl=2*L/(rho*v^2*A) L=lift (N) rho= air density v= air velocity A=wing area im doing a subsonic wind tunnel project where I am going to measure the lift for a low aspect ratio delta wing. should i use...
  27. Z

    Designing an Electro Magnet to Lift 1Kg Weight Precisely

    :redface: 1. i need to design an electro magnet that can lift a 1 Kg weight vertically with the minimum cost possible ANYONE GOT ANY IDEAS and i need it to be very presize i mean the measurements thanx
  28. S

    Aerodynamics in Automotives: Improving Lift & Drag

    Hi i am new in this forum, and i have a paper on aerodynamics, which is a bit general... Basically the paper is on how to affect lift and drag in automotives... could you help me with this... thanks
  29. X

    Calculating Diameter of Balloon to Lift 20 Metric Tons

    Homework Statement balloons are required to lift 20 metric tons. the pressure of helium is 101.325kpa. temp=21.1degcelsius. what should be the diameter of the balloon if it was spherical in shape in order to lift the weight? Homework Equations bouyant force?? The Attempt at...
  30. S

    Car Aerodynamics: Experimental trials not agreeing with lift theory, help

    Hi, I'm currently doing a research study on the effect of the presence of a rear car spoiler on the lift of a vehicle at low speeds As far as my understanding, with an increase in air velocity, there should be an increase in lift on the car. My trials however show that with an increase in air...
  31. J

    How Much Power is Needed to Lift 89 Skiers Up a Slope?

    1. A T-bar tow is required to pull 89 skiers up a 600 m slope inclined at 15° above horizontal at a speed of 2.5 m/s. The coefficient of kinetic friction is 0.06. Find the motor power required if the mass of the average skier is 65 kg. 2. w=F*d P=F*v 3. I found the...
  32. E

    Understanding Work in Lifting Heavy Objects

    Work to lift the weight?? A 1000-lb weight is being lifted to a height 10 feet off the ground. It is lifted using a rope which weighs 4lb per foot and which is being pulled up by construction workers standing on a roof 30 feet off the ground. Find the work done to lift the weight?
  33. Q

    What forces are involved in an inclined elevator boat lift?

    Hi, I have a question regarding the forces involved in an inclined elevator boat lift. Attached is a diagram of the setup. I was wondering what forces are involved. I know that there is a torque that is exerted on the inclined arm equal to the weight of the boat times the distance of the...
  34. R

    Calculating Height of Lift in Free Fall with Thrown Object

    Homework Statement A lift in free fall with Dr. Bhargav inside. In order to save his calculator he throws it up with 1 m/s from 1 meter above the floor of the lift. It reaches the sealing in two seconds. Calculate height of lift. The Attempt at a Solution As the wt in free fall=0...
  35. K

    Airplane Wing Lift: 20m2, 300m/s & 280m/s

    Homework Statement What is the net upward force on an airplane wing of area 20 m2 if the speed of air flow is 300 m/s across the top and 280 m/s across the bottom. Homework Equations The Attempt at a Solution I have a feeling that this is an easy question, but i just don't know...
  36. M

    Build Boat Lift w/ 10,000 lbs Capacity: Tips & Advice

    I am trying to build my own boat lift that uses plastic tanks submerged to lift the boat when they become filled with air. My problem is that I need to lift about 10,000 lbs and i don't know how large the tanks need to be ( how much water they need to displace ) to lift that amount of weight...
  37. J

    Candle Flame in Upward-Accelerating Lift: Why?

    How would a lift accelerating upwards affect the shape of the flame of a candle in it? My instinct says it would flatten it, but I'm not sure how to explain why. Any help?
  38. I

    Moller SkyCar: Wankel Rotary Engines and Lift

    i was reading on the moller skycar which has multiple wankel rotary engines powering ducted fans for lift, i was wondering if anyone had any information on how many pound of lift one of these engines on a regular ducted fan would have
  39. V

    How Do You Calculate Lift Force on a Banked Airplane?

    Need some suggestions... I have a banked airplane at theta degrees, with a radius, and velocity. What is the formula for finding lift force. Fc = Fn sin theta I believe, but that's the only formula I am aware of. Thanks!, -Mike
  40. B

    Toy Airplane Flying: Lift Force vs. Reaction Force

    Hi I've got a question concerning a previous question I've done. A person is holding a toy airplane which flys in the air with a constant radius. is the lift force the same as reaction force? is it equal to the vertical component of the centripetal force and weight force of the airplane?
  41. T

    How Is Lift Force Calculated for a Helicopter?

    A 4600 kg helicopter accelerates upward at 2.0 m/s^2. What lift force is exerted by the air on the propellors? I don't know how to do it. Please help :confused:
  42. A

    Relationship between Lift and Centre Of Mass (aerodynamics)

    Hey here is a quick question. I have a question on an assignment that is asking me to define lift in an aircraft (done) and its relationship to the aircraft's centre of mass. I'm unsure how to do that second bit as lift acts through the centre of pressure...not the centre of mass (also known as...
  43. S

    How could spring water lift a person?

    In an TV advertisement, a young man was lifted by an artificial spring water to a hight about 4 m. Supposed the man's weight is 800N, and the sectional area of the spring water is 0.2*0.2 m^2, and using the impuse-momentum theorem, I got a velocity of the spring water of 4m/s. Is this correct?
  44. P

    How Much Force to Lift a Pivoting Beam at an Angle?

    I have another question maybe someone can help me with. I have attached a drawing of a beam (tube) that is 42" long and weighs 50 lbs. The beam pivots at one end (red dot). If the beam weighs 50 lbs how much force is required to lift the beam to a vertical position if I apply force at a 45...
  45. P

    Fundamentals of Lift: Differential Pressure & Wing Shape

    Is lift essentially created because of higher pressure at the bottom of the wing compared to the top of the wing, causing a postive net upward force? With PA=F And the difference in pressure is created from lower wind or fluid speed at the bottom of the wing compared to the top of it...
  46. A

    Lift on an Airfoil: Bernoulli vs Newtonian

    Hi guys, I've heard that this topic has been discussed to death before but hopefully not here yet I apologise if it has been. I'm currently in high school we're just into bernoulli's equation and one of the applications is the airfoil. Our textbooks states that the fundamental source of...
  47. P

    Understanding Lift Force on Airplanes

    the force of lift excerted on an airplane is defined as F = Lc * D * v^2 * A where Lc is the lift coefficient, D is the air density, v velocity, and A the lift area of the wing structure. If i use SI units, the Force is expressed in Newtons. What I'm trying to grasp here, is how does this apply...
  48. S

    Question regarding Newton third law and weight in a lift

    emm, i m new member here maybe i m stupid and young enuf to ask these question, but i seriously nid help from u all to explain to me 1st, if we standing on a weighing machine in a lift, when the lift accelerate downward, the reading of W.M. wil decrease?and when accelerate upward the reading...
  49. A

    Why do we feel heavier or lighter at differenthis parts of the lift?

    Hi, i am currently doing a project on these questions. 1)why do we feel heavier when the lift startes to move up? 2) why do we feel normal in the middle? 3) why do we feel lighter when the lifts comes to a stop? although i know that the three laws of Newton is somehow related to...
  50. J

    How much lift is required to fly at level unaccelerated flight

    if an aircraft with a coefficient of lift of 0.05322 is traveling at the velocity of 240 kts at sea level, how much lift is required to fly at level unaccelerated flight if the aircraft weighs 800 lbs? (hint: trick question)
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