What is Drag: Definition and 747 Discussions

Profile Drag and Pressure Drag? Can someone please tell me the difference between profile drag and pressure drag if there is one??.

How much force does air resistance have on a freefalling object on Earth? No equations, please.

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...

Hi, I'm looking for a correlation of the drag force on a cylinder in parallel creeping (stokes') flow (i.e. the flow is alongside the axis of the cylinder). My length-to-width ratio is such that assuming an infinitely long cylinder is perfectly okay. Does anyone know where I can find such a...

Calculate velocity of the skydiver of mass M= 80kg as a function of time. The air drag coefficient D= 100g/m = 0.1kg/m. Assume that the skydiver has v=o at t=0. In my book high speed air drag is f=Dv^2. I found Vt= 88.5 m/s with Sqrt(mg/D). BUT this is not the V they are asking for :(...

Hello, I'm a french student. I will have to present a project for an entrance examination in a year's time and I've chosen to work on swimsuit. (is it considered as howework ?) The problem is that I find most of the information on english written websites, which makes it hard to understand...

Homework Statement A car starts at 100 m/s and deploys a parachute. After 10 seconds its speed decreases to 45.45 m/s. Calculate the distance the car has traveled in this duration. The effects of ground resistance are ignored. drag coefficient and planform area product (Cd * A) = 4 m^2...

Overall the sum of the forces of drag on an object must of course be negative. But is it possible to have areas of an object that contribute to negative drag? I have the pressure distribution over a NACA 0015 (symmetrical aerofoil about x-axis) at many angles of attack and I need to calculate...

Homework Statement This isn't exactly homework, but this seemed like the right place for this question. I'm working on an add-on for Orbiter - the space flight simulator - and would like to be able to determine the equation of motion for an object traveling at an initial velocity (v0), with a...

hello! i want to calculate th total drag (surface and pressure drags) for my prototype car, a project of shell eco marathon. Actually our prototype has the shape of an airfoil, its quite stream line.the Cd we use is 0.04 which is used for streamline shapes. ihave calculated the pressure drag...

Homework Statement Suppose a very light ball is thrown at a wall. The wall may be thought of as an xy-plane. At the moment the ball hits the wall, does it have 0 velocity in the x, y and z directions? Is drag on the ball (in each respective direction) small enough to be ignored at...

by how much will single-slotted Fowler-type flaps increase the drag coefficient of an aerofoil?

Homework Statement Consider an object that is coasting horizontally (positive x direction) subject to a drag force f = -bv - cv^2 . Write down Newton's second law for this object and solve for v by separating variables. Sketc the behaviour of v as a function of t. Explain the time dependence...

Induced drag of an airfoil should be inversely proportional to velocity^2 wiki states "Since induced drag is inversely proportional to the square of the airspeed" Ok but [Induced Drag = 0.5 * Density * Velocity2 * Wing Area * Induced Drag Coefficient] which is proportional to the veloicty^2 and...

Approximetly how much is the drag coefficient if orginally the coefficient is 0.02689. I know it depends on aircraft etc but I am only looking a rough estimate.

Homework Statement Droplets in a deodorant spray have mass of about (4x10^-12) kg and a radius of about 0.1mm. Estimate the terminal velocity of the droplets in Air of Viscosity (2x10^-5)Nsm^-2. Homework Equations Stoke's Law, F = 6pi rvu where r = radius, v = velocity and u = viscosity...

What are the effects of Spacetime "Drag"? I have learned that general relativity predicts that a rotating body (such as earth) produces not only a curve in the spacetime continuum, but it also 'drags' spacetime in the direction of rotation. 1) How is this possible? 2) What effects does...

Homework Statement Hi everybody, I'm new in the forum, I've been reading some post but couldn't find the information that i need. I'm making a game of soccer in 2d, and i need to calculate this: I have a basic physics simulation, and when a player has the ball i need to found the force...

I am teaching 7th grade Science. We are doing the shoe drag lab. To start we drag a shoe across the floor with a rubber band. Then we add a rock to the shoe and drag it again, measuring the stretch of the rubber band with a ruler. My question is: by adding a rock to the shoe, are we adding...

Hi, I am a university student of physics and currently have a project in which a "car" is propelled using only the energy stored in a balloon. Two possible ways of storing energy in the balloon are to inflate it and allow it to blow air out of the neck, or to twist it around and allow it to...

Do you guys know where I can buy some dummy parts and boards that I can practice drag soldering with? I would like to give it a try, but I don't want to ruin expensive working components.

I have been trying to find lift and drag coefficients in terms of pressure. So far I have found multiple equations. Below is what I have found after multiple research on the web. I am using these equations in LabVIEW. My input is going to be upper and lower surface pressure and I have to find cl...

Homework Statement A flat plate is orbiting at an altitude of 250 km around the earth, at an angle of attack Β=45 degrees. Assume that the atmosphere is composed of only atomic oxygen which reflect from the surface diffusely. Calculate the lift and drag if it has an area of 10 M2...

Homework Statement A yacht is of length 5m and travels at 10m/s. A scale model of length 0.5m is tested in a tank in order to predict drag on the yacht. Assuming that the fluid density and viscosity are the same for the yacht and model, can we obtain similarity? What is our best value for...

So if I double the velocity, aerodynamic drag doubles as well?

Information: "In downhill speed skiing a skier is retarded by both the air drag force on the body and the kinetic frictional force on the skis. Suppose the slope angle is θ = 31.5°, the snow is dry snow with a coefficient of kinetic friction μk = 0.0400, the mass of the skier and equipment is m...

Imagine separating a parabola into its different x and y components and linking them by the component of time. Scenario: Given: Gravity No Drag The velocity of the launched object is not sufficient to escape the gravitational pull. Ignoring: The change of gravity as the distance...

Hi, just found these forums, and they look very useful. I'm a second year Aerospace Engineering student, and as part of a project I'm modelling the first stage of a Saturn V rocket. I'm using a linear and non-linear model, and have all the equations sorted out. The only problem is I can't...

Homework Statement I have to compile a report for a project on the science behind a boat. Its a really open ended aissignement, I have no ideas where to start or what equations to use. I need the boat to go 20mph and therefore calculate what engine power I will need to make it reach that...

1. An F-15 touches down with a velocity of 100m/s. The only decelerating force acting on it is the drag, given by- How far does the aircraft move before it stops?2. D = 1/2 x Cd x ρ x A x v^2 (add in your own values for Cd, ρ, and A) a = (-D/m)3. Since the D depends on the...

In physics class we made a rocket and test fired it. Now we are given the thrust and we found out the max height of the rocket and the time of flight. Max Height = 76m Time of thrust/ upward acceleration = .8s Time of flight with only gravity acting until velocity is 0 . = 4.96s (not...

In physics class we made a rocket and test fired it. Now we are given the thrust and we found out the max height of the rocket and the time of flight. Max Height = 76m Time of thrust/ upward acceleration = .8s Time of flight with only gravity acting until velocity is 0 . = 4.96s (not...

We did a lab where we dropped three spheres into two different fluids, measured their velocities, and found drag coefficients. We were also asked some theory questions, and these are what I need help with. Spheres: 3.175 mm, 0.05 g Teflon 6.35 mm, 0.375 g, aluminum 12.7 mm, 8.36 g, steel...

Homework Statement The problem reads: "You are stopped at a red light, an identical car to yours pull up alongside. When the light turns green, you and the other car accelerate at a constant rate, but the other car's acceleration is greater. You see another stop light ahead and know you...

Homework Statement A blimp of mass 110 kg is pulled at an angle theta = 52 degrees downwards with respect to the horizontal for D = 7 km on level ground at a constant velocity v = 14 m/s. If the coefficient of drag (K in F = Kv^2) is 0.5 kg/m, how much work is done by the person pulling? As...

Homework Statement This is a real world problem and not a problem in a book, so if you feel I am missing some information just let me know. A ball is flying at 25 m/s The wind is blowing perpendicular to the trajectory at .44704 m/s \rho = \frac{1.17 kg}{{m}^3} Cd = 1/2...

Homework Statement The tanker has a weight 4000 MN and is traveling forward at speed 1m/s in still water when the engines are shut off. If the drag resistance of water is proportional to the speed of tanker at any instant and can be approximated by F=0.65v MN, determine the time needed for the...

I obtained lift and drag forces for an object I was testing in a wind tunnel and I wanted to know if it was possible to do a projectile motion problem with the following variables; I know the initial velocity of the object, V=76m/s, the possible launch angles = 30, 45, or 60 degrees, and...

Homework Statement Using a wind tunnel, I recorded lift and drag forces on an object and now I want to estimate where the object will land based on these forces. When I took the data from the wind tunnel, I changed the angle of attack at 2 degree increments from -10 to 30 degrees. This was...

I'm on a second bachelors -- how much will the first drag me down? I did very badly at my first shot at college. It took me 5 years to barely graduate with an english literature degree. I hated life in college, but I especially hated life after college. In that time I went up to Physics 2...

Homework Statement Missile Calculate the drag force on a missile 48 cm in diameter cruising with a speed of 270 m/s at low altitude, where the density of air is 1.2 kg/m3. Assume C = 0.75. Homework Equations Fd = -1/2p(v^2)CA The Attempt at a Solution...

PLEASE ANSWER BY TONIGHT!: What is an experiment to test drag force...? ...using only a tub about 14inx10inx7in, water, fishing line, a spring scale, fishing weights, and random household objects? we're suppose to design two experiments: one to test the effect of speed on drag force, and one...

Homework Statement A football of mass 0.4 kg travels horizontally above the ground. The ball experiences a drag force of DT = 0.01v2 where v is instantaneous speed. Immediately after the kick the ball has a speed of 15 m/s. How long does it take for the speed to drop to 12 m/s? Homework...

i have just started with physics and i have a project where i have to make a scenario where two cars are drag racing in a quarter mile race and the one with the highest top speed loses. i don't even know where to start.

In my effort of approximating drag constants for bullets, I have come across the McDrag program, by Robert L. McCoy. The disadvantage is that it approximates drag constants based on a few predefined shapes and a drag model (e.g. G1, G7), limiting it to only the simplest of bullets. Fully...

Homework Statement A sky diver of mass 79.5 kg jumps from a slow-moving aircraft and reaches a terminal speed of 53.0 m/s. (a) What is the acceleration of the sky diver when her speed is 30.0 m/s? What is the drag force on the diver when her speed is the following? (b) 53.0 m/s (answer in...

Homework Statement A stone with mass m = 1.8 kg is thrown vertically upward into the air with an initial kinetic energy of 310 J. The drag force acting on the stone throughout its flight is constant, independent of the velocity of the stone, and has a magnitude of 2.5 N. (a) What is the...

I know that standard formula is, FD = 1/2 CD *ApV^2 FD = Drag Force. SI: N CD = Drag Coefficient. SI: Dimensionless (Typical Values) A = Coss-sectional Area perpendicular to the flow. SI: m2 r = Density of the medium. SI: kg/m3 v = Velocity of the body relative to the medium. SI: m/s...

Homework Statement I know that standard formula is, FD = 1/2 CD *ApV^2 FD = Drag Force. SI: N CD = Drag Coefficient. SI: Dimensionless (Typical Values) A = Coss-sectional Area perpendicular to the flow. SI: m2 r = Density of the medium. SI: kg/m3 v = Velocity of the body relative...

2 cars drag racing question... Homework Statement The first car has a constant velocity of 40 m/s and moves 10 m before the 2nd car starts moving. The second car speeds up with an acceleration of 3.6 m/s^2. What is the time and the displacesment before the 2 cars actually meet...