Drag Definition and 713 Threads

Homework Statement Here, insted of trying to type it out, I will link a picture of the question from the book. Homework Equations The Attempt at a Solution The 3 questions I am having trouble answering are these: 1: How would you plot a graph of the data to obtain a straight line...

Due in an HOUR! Early Physics problem.. relating drag, weight, and speed. Homework Statement A 1.74 m wide, 1.48 m high, 1500 kg car hits a very slick patch of ice while going 21.0 m/s. Air resistance is not negligible. If friction is neglected, how long will it take until the car's speed...

Homework Statement In a simulation of machinery at a mine site, blocks of wood were used as shown in the following experimental set-up in which the two blocks – A and B – both of mass 15 kg are joined by a string over a frictionless pulley. Block A rests on a frictionless incline of 30º...

Can anyone PLEASE help me in pointing me in the right direction? I need to obtain drag coefficient calues for I-beams. I found a site stating it was 2.7, but it says nothing about the orientation?? I basically need the Cd-value for flow parallel to the I-beam, from the top and from the side...

Hello! I have just rediscovered this place since a few years back when I first signed up. This will be my first post, so forgive me if it is a bit long. I have been thinking about this for a while. So I have been thinking about buoyancy. I have learned that the buoyancy force is caused by...

I'm trying to calculate skin friction drag on a truck so I can compare it to pressure drag. I can find the formula and typical coefficients for pressure drag easily enough but I've had a hard time finding it for skin friction. So far I've found this...

What is the expression for Drag Force at very very High Renolds Number flow (>10^6) as we know the expression for drag force between Re1 and Re10^5 = 0.5kpAv^2 but this isn't valid aft 10^5 .. so ...

If a sphere is moving through air. Will it have more drag if it is spinning while moving or just moving ?

I was working on semi-realistic projectile dynamics. The first thing i took was what if a sphere is thrown upwards. g wud act downloads and there wud be drag. Drag=1/2kv^2 (leave k for the moment) (drag depends on v) g=g(R/R+h) (g depends on h) projectile is fired upwards with...

If we consider a sphere oscillates in viscous fluid with frequency w, then sphere has velocity u=u_0*e^{-iwt} In Laudau's book, he defined the velocity of fluid is: v=e^{iwt}*F where F is a vector with only spatial variable involved. The boundary condition then becomes u=v at |x|=R, where R is...

For a physics experiment, I'm testing the drag experienced by floating models with shape, wetted surface, and velocity as the independent variables. I placed the models in a flume tank and connected them to a hanging bucket via a string that passed over a frictionless pulley (see attached...

This occurred to me when I first heard of the Space Time Frame Drag effect, which was confirmed by the results of Gravity Probe B (GP-B). http://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic/" I am not a scientist or a mathematician, so I turn to my fellow humans who are. Do...

I got to thinking about this recently, when thinking about various proposed "renewable energy" systems based on tidal energy capture. Tidal energy is, basically, caused by the interaction of the kinetic energy of rotation of the earth/oceans, the kinetic energy of the moon's orbit, and the...

Hello everyone, i have a question, please help me with equations for magnus force and drag force...i have found an equations for drag force it's, Fd=1/2 * density * v2 * A * Cd . but i can't find equation for magnus force...can anyone tell where i can find it, or if somebody know, let me know...

Given a situation where an object is dropped at a certain height, how should the net force equation be written considering the fact that only gravity and drag acts on it? I'm stuck on whether the equation is written like this: \Sigma F = F_{g} - F_{d} Or like this because g is negative?: \Sigma...

Homework Statement Given a situation where a ball of mass m is dropped off at a height of h, find the equation that would give the velocity of the ball with respect to time given that gravity and drag are intrinsic factors. Homework Equations F_{g} = m g F_{D} = \frac{1}{2}pCAv^2...

hey guys, I am new here and this is my first post, but i need some help. the concept i am trying to explain mathematically is the acceleration a skateboarder (150kg) will have going down a hill (5 degrees bellow the horizontal) completely straight (2 dimensional), including air drag. to make...

Does turbulent flow create more drag due to the exchange of momentum between the slower moving particles and faster moving particles?

Hi I am currently trying to work out the drag coefficient of a car, I know the formulae to work out CD, this being CD=FD/0.5xρv^2A. I can not figure out how to find FD as the formulae for this requires CD. Is there another way to find FD? The information I have is as follows: Car Mass: 1350 kg...

Hi I am currently trying to work out the drag coefficient of a car, I know the formulae to work out CD, this being CD=FD/0.5xρv^2A. I can not figure out how to find FD as the formulae for this requires CD. Is there another way to find FD? The information I have is as follows: Car Mass...

I watch a lot of mythbusters and they constantly talk about the low pressure zone behind a car. I'm confused how does that create drag?

Homework Statement An object of 0.5kg is dropped from rest at an altitude of h=500 meters. It falls while being subjected to a drag force, defined as: fD = 2v . Derive explicitly: v(t), and y(t) and plot v(t) given the initial conditions; use: t between 0 and 0.4 seconds, and v between 0...

Hi everyone, I'm completely new to the aero engineering and have a question regarding drag. The lecturer explained it briefly, threw some formulae at us and now I'm confused trying to make sense of it all. So, i have these two formulae relating to drag: 1) D = 0.5(rho)(V^2)(A)(Cd) and...

The following link is a diagram of the motion of a pendulum I used in an experiment, where L represents the length of the pendulum arm: http://farm3.static.flickr.com/2144/2052427314_f42f4cc193.jpg?v=0 Does drag cause the angle θ to be smaller or larger than it would be with no drag...

Homework Statement On September 8, 2004, the Genesis spacecraft crashed in the Utah desert because its parachute did not open. The 210-kg capsule hit the ground at 311 km/h and penetrated the soil to a depth of 81.0cm . Assuming it to be constant, what was its acceleration (in m/s2 )...

A body falls into viscous liquid which causes the velocity to decrease at the rate proportional to the velocity. v=velocity(m/s) t=time(s) k= constant of proportionality The initial velocity of the body=30m/s k=0.3m/s^2 t=0.25s Solve for v in terms of t and k First step possible...

1. Homework Statement Here's the problem: http://www.flickr.com/photos/38401311@N05/5476715833/ 2. Homework Equations Here are the given equations: http://www.flickr.com/photos/38401311@N05/5477319510/ and http://www.flickr.com/photos/38401311@N05/5477320730/ 3. The Attempt at...

so let's say you have two masses attached by a spring in the middle. Also, there is a drag force proportional to the speed, that is F= -bv. I have this problem of writing the equations right. I envision, that I get the masses far apart, so I know there will be force exerted by the spring to...

I guess the Earth's surface pulls around the lower atmosphere with viscous drag effects? What about the upper atmosphere? Does it rotate with a slower absolute tangential velocity? If so, is there any pressure difference that caused by the difference in velocities that would cause any...

I have stuck at a step during derivation. Here it is. D=bv mg-bv=ma a=g-\frac{bv}{m} \frac{dv}{dt}=g-\frac{bv}{m} \frac{dv}{g-\frac{bv}{m}} = dt or, \frac{dv}{\frac{mg-bv}{m}} = dt \frac{dv}{mg-bv} = \frac{dt}{m} let, u=mg-bv \frac{du}{dv}=0-b \frac{du}{dv}=-b multiplying both sides...

I'm trying to obtain the drag force acting on a smooth cylinder at the exit plane of a wind tunnel. I took measurements of pressure at regular degree intervals around the cylinder. The pressure readings are in inches of water, and I know the freestream velocity and the stagnation pressure...

Homework Statement A drag racer, starting from rest, accelerates to ¼ mile with a constant acceleration whose magnitude is 12.427 m/s2. At the end of the ¼ mile, a parachute opens, slowing the car down and bringing the car to a stop after 40 seconds. From the time the parachute opened, how...

Drag at high Reynolds numbers is given by the formula: 0.5*\rho*V2*Cd*A Why does at the molecular (or at the micro) level the drag is independent of the viscosity?

hello! i'm doing a physics lab paper helicopters and changing the length of their wings. i was wondering if i could find the coefficient of drag for each helicopter. i have the mass of the helicopter, the time it takes to fall a certain distance and I'm assuming that the cross sectional area...

Homework Statement Drag=m(Mu*g+(V^2)/L) L=constant with unit of length initialV=V_0 how far the car will coast under this condition with initial V how long does it take to stop Homework Equations a=V*dv/dt The Attempt at a Solution there are linear and non-linear parts in this...

For fun, I wanted to crate a program that dealt with 2d projectile motion w/ wind resistance. Specifically, where the object started from rest at a given height. I looked up several equations that dealt with wind resistance. Specifically, drag force. Drag force was defined as Fd = CdPAV^2/2. So...

Homework Statement A particle of mass m and electric charge q>0 is subject to a uniform, constant mag field of \vec{B} = B \hat{k}. At t=0 its velocity vector is \hat{v}naught which lies in the x-y plane. The particle is also subject to a linear drag force fd=-b\vec{v} a)Draw a free body...

Homework Statement This is a small part of a problem I'm getting stuck on. I'm going to skip past the beginning steps to a part that I know is correct before I get stuck. We have a baseball thrown up into the air, with quadratic drag. I'm attempting to solve for an equation of motion y(v)...

I'm kind of stuck in my search, hoped to be able to find some answers on this board. Anyways, I've been taksed to design a slow speed mixer and I'm trying to look up information beyond Stokes Law of FD = 6 pi r V u The fluid to be mixed is approx. 100000 poise, incompressible fluid. I'm...

While I understand this is a basic question, I am a beginner with regard to fluid dynamics etc. To start, say you have a propulsion system capable of X Newtons and a weight of Y kg. I realize max speed occurs at the point at which the force of drag is equal to the force of acceleration, and the...

Homework Statement To demonstrate the tremendous acceleration of a top fuel drag racer, you attempt to run your car into the back of a dragster that is "burning out" at the red light before the start of a race. (Burning out means spinning the tires at high speed to heat the tread and make the...

Homework Statement How can I calculate the drag of different missile/torpedo shapes in water? I have five different shapes, similar cylinders with different "noses" One is a long cylinder with a flat nose, another is a cylinder of the same diameter with a hemisphere nose. Third and fourth...

Homework Statement Suppose a block sliding on a slippery horizontal surface experiences a drag force F=-cv3/2 where c is a positive constant. At time t=0, the block is at position x=0 with initial positive velocity. Find the velocity and position as a function of time. Derive an expression for...

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 I have to make a plot. This plot must illustrates a position of a ball, which is falling. My problem is that I don't know what v is in this equation. drag force= -C * ||v(t)|| * v Homework Equations To calculate the velocity: v(t+dt)=v(t)+a(t)*dt where t is time...

Homework Statement A projectile of mass 0.1 kg traveling horizontally through the air with speed v(t) experiences a drag force DT (t) whose magnitude is given by: D (t ) 0.001 [v (t )] 2 At one instant, the projectile’s speed is measured to be 100 m/s. Calculate the speed of the...

Hi, I am trying to caculate the aerodynamic drag on a weather balloon that's climbing through the atmosphere. Of course, the velocity is very low here, about 4m/s. Such a balloon is an almost perfect sphere. So I am trying to fill in the drag equation, but I still have two unknown...

Hello! First time poster, long time lurker. I've been doing my own independent study of fluid dynamics (not recommended, i know!) and I've hit a wall. I'm trying to imagine problems of fluid dynamics other than the "river and pipe" variety to confirm that I'm really getting this drag stuff. I'm...

Homework Statement I don't know if it's possible but I am doing a physics EEI on drag. I know to find drag you need instantaneous velocity which can be found through (change in x/ change in t) but i cannot find displacement unless i find velocity :S.. Homework Equations d = 0.5 x p x...