Drag force Definition and 166 Threads

Homework Statement An object is influenced by 2 forces: environmental force F1 = 42 tons and a hydrodynamic drag factor F2 = 200 kN. These forces are directed against each other (one attempting to 'weaken' the other one). The corresponding mass of object is 10,112 tonnes. I am trying to create...

The drag force can be affected by the velocity of the object relative to the fluid. Does that mean the wind affects the drag force, since it changes the velocity of air particles?

Relation b/w slip ratio and drag force...Race car Vehicle Dynamics help... hii guyz... this is the first time i am posting on this forum and hope i ll get help... I was going through Race car vehicle dynamics by milkins and found a relation given on pg 64 which says... Drag...

Hi, An object is falling near the surface of the Earth. We assume there is a drag force acting on it due to the air molecules. It's initial conditions are such that it rotates and is in a chaotic motion. Will the object will fall in the end in such a way to minimize air drag? And if yes -...

Homework Statement Consider a rocket is subject to linear resistive force, f = -bv . \dot m is constant. Use the equation: m \dot{v} = -\dot{m }v + f to determine the velocity of the rocket : since the rate of mass lost is constant let \dot{m} =k vex = nuzzle velocity v = \frac{k}{b}...

Homework Statement Find work of drag force in term of proportional to Velocity (Like: Wd=kV^n ,when k=constant value n=Real number) Homework Equations (Fd=1/2*ρ*v^2*Cd*A) The Attempt at a Solution I've a problem with my science project. I try to find the terminal velocity of a...

If you have a falling object and wind in the horizontal direction, the object ends up falling to the ground at an angle. Why does the drag force only have a vertical component? Thanks!

I am doing a project where in a pedestal fan is alternatively powered using a flywheel. The flywheel is brought to some initial angular velocity by the electric motor. Now, if the power goes off, the fan blades would be coupled to the flywheel and it continues to rotate for the next 10 minutes...

Homework Statement a ball makes a free-fall with zero initial velocity and an arrow with 25 m/s initial velocity is thrown to shoot this ball at the same time. The ball is initially h=38 m higher than the arrow. a) Assume no drag force then how long after does this collision occur? At...

For the motion of a spherical ball under water, can its drag force be calculated by knowing only its mass and deceleration?

Basically, BB ammos were shot from an airsoft gun into a water filled tank. The experiment was recorded using a video camera. I can calculate the approximate instantaneous velocity of the bullet under water at a given time using Logger Pro. 1. Relevant equations Drag force = 0.5 ρAC0v2 2...

Homework Statement A projectile of mass 1300kg is launched from the ground (x =0, y =0) initial velocity components Vx=Vy=108m/s aerodynamic drag force is of magnitude C(V)^2 where C = 0.6 Homework Equations Finding the range and angular momentum initial and final The Attempt...

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...

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 ...

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...

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...

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...

Homework Statement Now assume that the wind (air) is blowing with velocity va/0 = αi + βj relative to the ground, where α and β are constants. You may find it useful to consider this problem in terms of the velocity of the wind (air) relative to the ground, va/0, the velocity of the projectile...

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...

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

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 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...

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 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...

"A two-dimensional structure is tested in a wind tunnel with an air density of 1 kg/m3. The wind tunnel is 1 m high, with upstream and downstream pressures of 1.5 kPa gage (i.e. above atmospheric) and 1 kPa gage respectively. If the mean velocity of the entering air is 30 m/s and the downstream...

F = -kv2 A fishing boat of mass m moves through the water in the +x direction. At time = 0 and x=0 it shuts its engines off and begins to drift. It experiences drag according to the above equation, calculate the boat's speed as a function of time. I've tried taking F = ma so a = -kv2/m...

Homework Statement Air at 20kPa and 20°C flows across 5cm diameter cylinder at velocity of 20m/s. Compute the drag force exerted on the cylinderHomework Equations the formula should be use is this, FD = CD*A*den*V^2 / 2 where FD & CD is the drag force and drag coefficient, respectively The...

Knowing the weight, the mass and the acceleration of the object, how can I find the drag force? I used the following formula --- "Weight – drag force = ma" --- but I'm not sure whether it is right or wrong. Mass = 0.14 Weight = 1.34 Acceleration = 8.63 1.34 – drag force = 0.14 x 8.63...

Hello PF'ers, I'm having a bit of conceptual trouble with understanding the drag force derivation. I take the drag force as being D \ = \ \frac{1}{4} \ A \ v^2 . I want to imagine dropping an object from the highest point at which the equation w = mg will be a satisfactory...

Homework Statement A ball of mass 0.5 kg traveling horizontally through the air with speed v(t) experiences a drag force DT (t) whose magnitude is given by: DT (t ) = 0.01[v (t )] 2 The speed of the ball is found to reduce from 10 m/s to 8 m/s over a time interval t, during which time...

What is the drag force on a 1.6 m wide, 1.4 high car traveling at A) 10 m/s B) 30 m/s I'm getting 68 N for part a and 615 N for part B using equation D=.25pAv^2 P= density of air (1.22 kg/m^3) and A is cross sectional area of obect as it faces the wind). *I plugged in 1.22 for p...

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...

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...

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 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...

A reasonably large object moving though air experiences a drag force proportional to the square of its speed. If an object is falling vertically downward at half its terminal speed, how does the drag force acting on it compare to the force of gravity? express your answer as a multiple of Fg

Hi, I'm looking for the formula to get the velocity value from a drag value. I found plenty of resources to do it the other way around (velocity to drag) but no luck to get it the way I need it. This website seems to have it but they don't provide the rule and they actually want money to...

I am interested in calculating the drag force acting on simple objects (cube and sphere) as they passes from a liquid (water) into a gas (air). I can calculate the drag force as the objects travel through a uniform medium, but I am wondering how the drag force on an object changes as it passes...

Hi In a Drag problem, I'm trying to calculate the drag force but I don't know the drag coefficient? Is there any way to calculate it? Thanks

Hello, First time post long time lurker! I've got an interesting project I am working on which involves a few MechE subjects. The overall goal (for now) is to determine the drag force of a cylindrical cone headed object in sand under various pressures. The movement of the cylinder is the tricky...

Homework Statement For a touring bicyclist the drag coefficient C(where f of air = 0.5CApv^2) is 1.04, the frontal area A is 0.462 , and the coefficient of rolling friction is 4.60×10−3. The rider has mass 53.0kg, and her bike has mass 11.1kg. Note: p is density of air (1.2kg/m^3) To...

Homework Statement You dive straight down into a pool of water. You hit the water with a speed of 6.5 m/s, and your mass is 75 kg. Assuming a drag force of the form Fd = (−1.00×104 kg/s) v, how long does it take you to reach 2% of your original speed? (Ignore any effects of buoyancy.)...

Homework Statement You dive straight down into a pool of water. You hit the water with a speed of 7.0m/s, and your mass is 75kg. Assuming a drag force of the form F_D = (−1.00×10^4kg/s)*v, how long does it take you to reach 2% of your original speed? (Ignore any effects of buoyancy.)...

Homework Statement You dive straight down into a pool of water. You hit the water with a speed of 6.5 m/s, and your mass is 65 kg. Assuming a drag force of the form F_D=cv=(-1.2*10^4 \tfrac{kg}{s})*v, how long does it take you to reach 2% of your original speed? (Ignore any effects of...

In one dimensional cases, will the velocity of a particle tend to the terminal velocity unregardless of any combinations of forces? I try to investigate this equation: mv'+bv=F(t) Using the mathematics theorem at the botton, I found that v --> F(c)/m as t tends to infinity. (where c is some...