Lift Definition and 593 Threads

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...

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...

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...

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...

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.

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

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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.

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...

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?

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 ?

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?

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...

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...

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.

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...

Hello everyone, When you go down a lift, are you actually falling down. Is the lift carrying you down, or are you falling down due to gravity towards the lift, if the lift goes too fast would your head crash? Sorry if my thinking is completely wrong. Ok now apparent weight is from the...

Hi, Imagine you have an object where the weight is equally divided. What would be the formula to calculate the force needed to lift the object up to a distance without lifting it up completely. For example, a push-up, your feet keep touching the ground but you push your self up. How would one...

What's the equation for the force of a lift. Drag formula is 1/2 ρ∆v^2 C A. And if you need the constant how would i determine the lift constant for a semi circle shape which spins sideways and has an acceleration of approximately 8.5 m/s down (should be gravity which is 9.8 ms/s). It is...

Pretty simple question: Is it possible to completely calculate Lift and Drag from the pressure distribution over an airfoil? Atm, I have Lift worked out as well as the Induced drag ( correct me if I'm wrong. ) but am having trouble working out how it would be possible to get the skin...

http://www.harborfreight.com/1-2-half-ton-capacity-pickup-truck-crane-1647.html I bought this truck crane for my father. How could i calculate the force needed on the handle to lift a given load? I could measure it but I am interested in how the math is done. For simplicity i'll assume the...

Homework Statement How many cubic meters of helium are required to lift a balloon with 400kg payload to a height of 8000m where the density of air is 0.460kg/m^3 and the density of helium is 0.180kg/m^3. Assume that the balloon maintains a constant volume. Homework Equations \rho = M/V...

Homework Statement If a man has an average useful power output of 41.4 W, what minimum time would it take him to lift fifty 15.0-kg boxes to a height of 1.88 m? Homework Equations 1/2mv(final)^2 mgy(final) = 1/2mv(initial)^2 mgy(initial) P=W/Δt P=Fv The Attempt at a Solution...

Homework Statement Using sketches and equations briefly describe how Bernoulli's equation and other factors cause lift force to be generated by a wing. Homework Equations The Attempt at a Solution I'm struggling to find anything else that causes lift except bernoullis! please help!

Homework Statement A light spring force const. k hands from ceiling of an accelerating lift with a block of mass m attached to its bottom end. Block is held stationary (in lift frame) with the string at its equilibrium length while the lift is accelerating at a rate Ag where A is between -1...