Drag Definition and 713 Threads

I have been around Sailboats all my life. For the last 25 years I have built and raced r/c model sailboats. My current question, I hope, can be more of a discussion than just a simple question and answer. Since I am into the design of all aspects of boat and sails. I have a question about...

Homework Statement Consider a particle in a gravitational field that is also subject to a resisting force proportional to the velocity squared ( Fdrag = + or - cv2). a) Find the terminal velocity, vT, for the object as it falls. b) Show that for an object dropped from rest that the velocity...

How would one calculate the drag on a projectile (in this case a 1cm3 cube) that was launched at 0°. The vertical drop, initial velocity, distance, and time (taken to travel distance) where measured. I want to say that I could compare these experimental drop (bellow hight that projectile was...

Homework Statement Homework Equations Sum of force a = dv/dt v = integrate a + C The Attempt at a Solution I found the equation in terms of final v, initial v... however, on the right hand side, there is another v, and I think it is time dependent, so I am not sure which value should I...

Homework Statement Homework Equations F=ma Sum of force The Attempt at a Solution Not sure if my a is correct, but actually, I need to have it in imperial (US) unit,[/B]

I need an equation that solves for the height of a projectile at a specific x position. The known variables are spin of the ball, initial position, initial velocity, initial launch angle and the drag and lift coefficients.

As I have looked through the internet and did my research I have found some information on how to calculate the drag coefficient, however none of what I have search for matches what I need. Currently I am doing a physics assignment for grade 12 and I am investigating the physics behind...

I'm trying to add flight physics to a 3d game. When I try to calculate drag I sometimes get a force that pushes the aircraft backwards if I make the wingspan very large (for example). I have set up a simple scenario: A flat rectangle sheet falling down due to gravity. If I make the gravity...

Just to the point.. How Turbulence Intensity affect a drag? As far as I know if there is decrease in Turbulence Intensity, the coefficient of drag will decrease to, but I don't know why the reason behind that. Also, the relationship with flow separation too. I hope someone can help me with...

I was wondering what would be the car mileage, if we reduce the current Drag coefficient from 0.30 to 0.15? Or to 0.10?

hi ...this is may be stupid question citing that there is so much information about the subject.. i understand that friction is possible in space...ie rub two things together and a resisting force will create drag on both surfaces and heat will be produced... But can space vacuum create drag...

Hello! I am predicting the peak altitude of a model rocket based on some ground tests. I know that Total Force on the rocket=Thrust-mg-kv^2 but am stuck as to which value for 'v' to use? Is it the velocity of the rocket with the effects of gravity and air resistance taken into account or the...

Hello everyone, I am predicting the altitude of a model rocket based on some testing I did where I found the impulse of a little single stage model rocket motor. I am wondering how to incorporate drag into my calculations to make it more accurate. I know D=Cd*rho*v^2*A and I can definitely find...

In the attached picture, can I say that there is a lift force in the Y-direction, and a drag force too in the same Y-direction? FL proportional to V_fx2 ? FD proportional to V_py2 ? Is this equation of motion for the Y-direction correct here: ma = − mg − FD + V(rho)g + FL The lift force is...

Does the induced drag increase with an increasing air speed for a given angle of attack? Most graphs I found online seem to suggest that the amount of induced drag increases as the speed increases but they actually allow the AOA to vary so I was wondering for a case of fixed AOA(ground roll for...

I was reading this thread on Reddit about estimating drag using only a temperature profile. I was reading the responses, and I feel like most of them are missing something. Since this forum is more science-focused, what do you guys think...

Homework Statement There isn't really a "problem statement", but more so a conceptual prompt. Say you throw a ball in the air with some velocity V. The work done due to gravity and drag is Mgh + Fdragd. What I don't know how to do (and there is no additional information, the prompt is very...

Hello, I was doing my physics coursework, and blew a hairdryer at my makeshift aerofoil across distances of about 10cm and wind velocities of 8-11 m/s, then measured the lift off of a balance. I found they were proportional, exactly (!?), after doing some research I found drag is proportional...

Hello there, I'm trying to write a sailing model simulator (for ships with sails) i got buoyancy force and gravity force calculated so far. Before i go any further i need to tell you how i am calculating anything, and what is my ship exactly. First of all i am making that on a phone, it looks...

I was given the task to create a hull which must be propelled by human and solar power; I have found it difficult to obtain existing hull designs with their respective coefficient of total resistance so I am looking for a way to calculate the total hull resistance for a hull of my own. I...

I recently completed a lab using an online projectile simulator about the range of projectiles. I launched a projectile with different initial speeds (5 m/s, 10 m/s, 15 m/s, 20 m/s, and 25 m/s). For each trial, I did the launch with and without air resistance and I plotted Range (with Air...

Homework Statement Assuming that the drag force magnitude is given by the equation D= bv, where b is the drag parameter and v is the instantaneous velocity magnitude of the object. (a) Show that the vertical displacement through which a dropped object must fall from to reach X% of its...

I was given the following drag profile for a spacecraft upon reentry. I understand that the moment it enter's Earth's atmosphere it will be accelerated due to gravity and pick up speed which in turn increases drag however I don't understand why drag then decreases. Wouldn't density cause...

Hi everyone, I'm working on a project for my electromagnetics class which asks us to design an electrostatic launch system that can propel an object into space. Though the bulk of the project is supposed to be about designing the accelerator plate array, I got really interested in the whole...

Hi there, I have recently been experimenting with solid metal spheres being let to fall through fluids of different viscosities and have recently been introduced to the 'Ladenburg correction'. This correction multiplies the measured velocity of the sphere to obtain the 'correct' velocity used...

Homework Statement Drag racing usually involves two cars racing each other over a set distance. Although distances range from 200 m to 1 km, the 400.0 m drag race is the most popular. This race tests a vehicle's acceleration and top speed. Data collected on a race by a dragster- Distance (m) |...

Homework Statement Two packages are dropped from an airplane. A parachute can increase the cross sectional area of each packages by a factor of 31. The parachute on package 1 fails to open, and the terminal speed of package 1 is 10 m/s. The parachute on package 2 opens. What is the terminal...

Homework Statement Given the drag equation and a projectile's initial kinetic energy and mass, find the distance in which it will come to rest (or at least, become absurdly slow). Homework Equations https://en.wikipedia.org/wiki/Drag_equation The Attempt at a Solution Force = .5 * fluid...

Okay so here is my idea, not really sure how well (if at all) it would work but I am wondering if it would be possible (assuming battery technology is good enough) to ionise air in front of a formula 1 car (or plane or whatever) giving it a charge (like the way lightning works) , then creating...

I have a peculiar problem of calculating a trapezoidal bar (used as sacrifical anode) in offshore substructures. Can anyone advise me how to calculate the Cd value of such a section. Flow is along the length of the bar.

Homework Statement A long cylindrical antenna of 9 mm (0.009 m) diameter is mounted vertically on a car moving at 100 km/h (27.778 m/s). Antenna is 920 mm long (0.92 m). Calculate the power required to move antena through the air with standard kinematic viscositiy [FONT=Times New Roman]ν =...

Hi All! See the picture. A-Consider a flat plate physically moving perpendicularly through the air. B-Consider this same flat plate sitting perpendicularly and stationary now in a wind tunnel where air is made to flow. Accordingly if airspeeds, areas etc are similar, the 2 situations...

Homework Statement A sky driver reaches his terminal velocity of 373 ms^-1 and deploys his parachute at a height of 1500m, the drag force =bv^2 and weigh can be ignored. Find an expression for velocity as a function of distance traveled from the point the parachute was deployed The Attempt at...

Experts - Why they don't increase altitude of ISS to overcome slight atmospheric drag it faces. Due to this, they need to make altitude corrections frequently to ISS. I want to know, why they can not put ISS in higher orbit where there is almost nil atmospheric drag (or may be altitude...

Wikipedia says that: Atmospheric and gravity drag associated with [space] launch typically adds 1.3 to 1.8 km/s to the launch vehicle delta-v required to reach normal LEO orbital velocity of around 7.8 km/s (28,080 km/h). Does anyone know, or know how to calculate/estimate/simulate the delta-v...

Hi, I am working on a video capture project in which i am videoing the projectile of a ball that is being thrown in the air and trying to fit it to a curve for the expected trajectory of a projectile with quadratic drag.I am running into the issue that in order for my expected trajectory to fit...

1. Homework Statement A 4-wheel drive car of mass M = 2100 kg accelerates from rest to 100 km/h in 3.40 seconds, and we will assume that the acceleration is constant. In the following, ignore resistance from the air and the rolling friction of the wheels against the surface. The wheels are...

Hi guys, I'm an arts undergrad student with very little knowledge of the sort of physics I'm about to ask. I was wondering if there is a calculation to work out the differentiation between running at a particular speed say 10mph against wind coming towards you at 15mph. As well as it being on...

Homework Statement Suppose you drop a feather and a steel ball of equal masses (0.014 kg) at the same time from a height of 2.2 m and you are told that the feather hits the floor 3.5 s after the steel ball. Estimate the value of the terminal velocity of the feather in air. Then, estimate the...

Homework Statement I attached a screen shot of the problem. Homework Equations D= 1/2 C p A v^2 bv=mg The Attempt at a Solution I spent 3 long hours on this problem. I confused myself even more. Please help me understand what is going on.

Homework Statement So there is a falling object, you have to take into account the boyant force, the pull of gravity and the drag force A time dependent distance equation is what we're looking for Homework Equations Fd=CdApav2/2 Where Fd is the drag force Cd is the drag coefficient A is the...

In the aeroplanes, the drag is in the opposite way of the direction of the aeroplane. My questions for wind turbine: 1) Why "wind speed" and "the drag on the blade" is in the same direction? Shouldn't be the opposite? 2) Are freestream velocity and the wind speed same thing? 3) Are the drag...

1. In general, dense fluids (such as water) produce a drag force that is directly proportional to the speed of an object moving through them. Suppose a boat is moving through the water and experiencing a fluid drag force of F=-8 v. Suppose the boat has a motor which can output up to 450 Newtons...

Hello everyone. Recently I have had a lingering need to (in a loose sense) conceptualize the aerodynamic resistance of an object traveling at high supersonic velocity. However it has been a long time and I am rusty on my physics. I am looking for a ballpark figure on the Newtons and Joules (1...

Homework Statement Coal miners often find mice in deep mines but rarely find rats; let’s see if we can figure out why. A mouse is roughly 5 cm long by 2 cm wide and has a mass of 30 g; a rat is roughly 20 cm long by 5 cm wide and has a mass of 500 g. Assume that both have a drag coefficient CD...

I've read that drag coefficient depends on the shape of the object but I am confused as to what shape means. Does it mean geometric shape or is area included in that? Say I have one sphere of radius r and keep fluid velocity, density, and viscosity constant and find its drag coefficient. Would...

The part that I roughly understand: 1) Drag equation, drag increases by square of velocity, thus if it was only factor to be taken into account then the lower speed the better. 2) In case of cargo ships there is a policy of decreasing speed to reduce fuel usage, called "slow steaming". It...

Homework Statement [/B] A baseball of mass m is thrown straight up with an initial velocity v0. Assuming that the air drag on the ball varies quadratically with speed (f = cv^2), show that the speed varies with height according to the equations. Where x_{0} is the highest point and k = c/m...

Hello, I would like to know how to calculate the drag force per unit length of an infinite cylinder with it's axis parallel to the flow field, I had read about a post here previously titled " Drag force on cylinder in parallel flow" but the slender body approximation is not valid for inifinite...

What is the difference between viscuous force and drag force? Are they the same?