Questions tagged [drag]
The force on a body resulting from it's motion through a fluid (gas or liquid). This force is directly opposed to the direction of travel.
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Flight time of spherical bullet fired horizontally versus dropped vertically / effect of crosswind on spherical car
Would a spherical bullet fired horizontally from a musket stay aloft longer than a spherical bullet dropped from the same height?
I know two similar questions have been asked (Will a bullet dropped ...
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Friction at high speeds
I am reading a book which mentions that frictional force is not exactly proportional to the normal force at high speeds. Quoting:
Once the bodies slip on each other frictional force is, $kN$. This ...
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1answer
55 views
Is it possible to find $\mathbf{v}$ explicitly when $\mathbf{F}$ varies with $\mathbf{v}$?
I have the following problem (NO, this is not to ask for a solution to this problem).
A block is placed on a plane inclined at an angle $\theta$. The coefficient of friction between the block and ...
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2answers
35 views
Why is the velocity in the horizontal direction constant for 2D projectile motion?
For 2D projectile motion, why is the velocity in the horizontal direction constant?
I learned that we neglect air resistance, but why?
And isn't there horizontal acceleration at the beginning when ...
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1answer
32 views
Damped harmonic oscillator's maximum displacement [closed]
I want to know the maximum displacement $x_0$ of a mass $m$ on a spring with spring constant $k$, in the case that the system is damped with damping constant $c$, and where the initial velocity $v_0$ (...
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Future space travel involves no (or little) drag? [closed]
To celebrate the start of the (Western-European) vacation season, I was pondering about future space travel and the related question of aerodynamics in the thin interstellar medium. Based on what I'll ...
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3answers
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Why is the drag force proportional to $v^2$ and defined with a factor of $1/2$?
$$Drag = \frac{1}{2}C_d \rho Av^2$$
I understand that the strength of the drag depends on the density of the fluid the body passes through, the reference area of the body, the drag coefficient, and ...
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1answer
26 views
Effect of air resistance of the period of a pendulum [duplicate]
Does air resistance increase or decrease the period of a simple pendulum?
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1answer
25 views
Calculate the kinetic friction velocity vector from the kinetic friction force in a simulation
I am doing (programming) a simple kinematic 2D simulation on blocks. The idea is that the block will have a force applied.
1) From the force and mass I calculate the the acceleration vector (will ...
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1answer
33 views
Why is it easier to catch mosquitoes with your hand when your hand is wet?
Recently I've noticed that it's significantly easier for me to catch a mosquito with my hand if my hand is very wet (e.g. from having washed my hands and not yet dried them, or from being in the ...
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1answer
85 views
High velocity mushrooms?
So y’all know meteoroites burn up in our atmosphere I’m looking for an equation or something that will allow me to calculate how fast a substance can move before it starts to burn up. Specifically I’m ...
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Does air resistance have a greater affect on longer pendulums than shorter ones due to the greater exposure it has to air?
I'm thinking, because longer pendulums travel for a greater time period through the medium of air, air resistance will have a greater affect on the pendulum bob (and string) and so the angle the ...
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1answer
64 views
Is Verlet method suitable for to solve projectile motion with quadratic drag?
Consider the following non-dimensional equations of projectile motion in presence of air resistance,
I understand it can be numerically solved using the mid-point method, but can I also use Verlet ...
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71 views
Projectile with air resistance from a given hight
Objects take same time to fall a given height independent of their horizontal speed when air resistance is ignored, is this also true when air resistance is not ignored? In presence of air resistance, ...
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Davis formula application
So I stumbled upon the Davis formula for trains while doing some researches about my project but I don't know how to apply it (programmatically) :
Let's say for example this variant :
$$R'=1.3+\frac{...
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1answer
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Train Physics Simulation
It's my first time asking here so bear with me.
I'm a computer scientist, and I'm working on a train simulator project. I'm having quite a difficult time understanding all the physics and formulas ...
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Fuel efficiency of supersonic planes
I stumbled upon an interesting plot; in particular, the dependence of wave drag on the Mach number:
It is curious to see that the drag coefficient drops so abruptly in the supersonic regime, but I am ...
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Individual air molecule momentum exchange
Background:
Looking at this illustration about solar radiation pressure on a perfect reflective surface, incident photon exchanges its momentum to the slanted surface which provides a reaction force ...
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2answers
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How do you find the minimum height to open a parachute for a safe landing?
What concepts/formulas can be used to find the optimum/minimum release height of a parachute?
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What happens when the drag force exceeds the weight of an object falling into earth?
Let's say a meteor is coming towards earth. It's not accelerating, but it does have an initial velocity. This meteor is shaped so it has an insane amount of drag, enough to even exceed its weight (not ...
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4answers
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Why the book falls faster than a feather, dropped from the same height? [duplicate]
If I dropped book and feather from same height. Why book falls first, however book has more windage(air resistance), more area(square) than feather?
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3answers
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Why can I throw a larger stone farther than a smaller stone?
Recently I was throwing stones(don't ask me why) when I noticed that there seems to be an optimum weight of stone so that it travels the farthest.
If I generate the same amount of force each time(and ...
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1answer
12 views
Can't find coefficient for my IVP
In my problem I have to set up an IVP and model freefall with air resistance before the bungee starts being pulled on. Beta being my airresistance coefficient. I have:
$$ mx'' + \beta x' = f(t) = 0$$
...
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1answer
57 views
Why is the rudder of a ship shaped like a wing?
I don't understand why lift gives an advantage, it could be working the same
even if it was just flat.
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Drag Coefficient of a rounded nose cylinders
According to this page
The drag coefficient of a rounded cylindrical bodies is given by this graph
Then the drag coefficient of a cone for a half vertex angle ε is given by this graph.
How can ...
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Viscosity from terminal settling velocity of a sphere
I don't have an attempted answer to this question because I don't really know where to start. The Tip says to start from a force balance for the sphere, but I'm not sure on how to do that.
I know ...
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1answer
91 views
How to find drag of a cylinder?
How can I find a drag on the cylinder placed in uniform water flow, if I know a velocity field around it?
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42 views
Coefficient of drag past a cylinder
I have a lab assignment to determine a drag coefficient of a cylinder perpendicularly submerged in water. I have a measured velocity field and cylinder diameter. How can I find Cd? (I heard of a ...
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65 views
At what speed in air would a solid object turn to plasma?
Just curious, friction can heat up what ever is moving. The faster something moves the quicker it heats up. Is it possible in the perfect scenario to turn a speeding solid object to plasma through ...
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1answer
47 views
Which ball touches the ground first? Different explanations
Two balls with the same shape and volume but very different masses are dropped from the same height WITH air.
The heavier ball should land first, but is it because of terminal velocity (see this ...
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0answers
40 views
Does cross-sectional area affect the air time of a vertically thrown object?
Factoring in air resistance, I have two objects A and B of identical mass, however have different cross-sectional areas. A has a larger cross-sectional area than B. If I throw both objects directly ...
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43 views
Derivation of the wind load formula
I am trying to derive the wind load formula:
$F_d = \frac{1}{2} \rho v^2 A C_d$
in which I assume the drag coefficient to be equal to 1.
My starting point is that the momentum of a rectangular wall ...
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0answers
40 views
Where exactly does the drag force come from when using eddy currents?
I read the Wikipedia page on eddy currents and the explanation for braking confused me
At the leading edge of the magnet (left side) by the right hand rule the counterclockwise current creates a ...
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2answers
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Does damping force depend on frame of reference?
I learn that damping force with regard to forced damped oscillations is given by
F = -bv where is the velocity of the object measured from ground frame. Suppose we are in a frame which is moving with ...
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Force applied by horizontal wind on object
Hello, I have a question for a project I'm currently doing:
In a tunnel with no gravity, there is a constant wind blowing through.
A sphere in the middle of the tunnel is completely motionless to ...
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1answer
36 views
Calculating magnetic strength required to hold an objects weight + wind speed?
Note: I'm a bit new to this subject, so I'm looking for some general answers, ballparks, and direction to continue my research.
Scenario: I have three electromagnets capable of X amount of holding ...
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2answers
42 views
The force of wind on baseball
Does anyone know of an equation that I would be able to use for the force of wind acting upon a baseball? I am working on the projectile motion of a baseball with air and wind resistance. I have the ...
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0answers
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Wind Force of a projectile
I am currently working on a program that models the projectile motion of a baseball with air resistance and wind acting upon it. However, I cannot find the equation to calculate the force of the wind, ...
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Drag of flat plate at any orientation in 3D
I am trying to calculate the force vector on a flat plate caused by wind, when that plate is not perpendicular to the wind.
Imagine a sailboat, and assume that its sail is a rectangular flat plate. ...
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1answer
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Parabolic motion of a projectile
During a conference I have listened that an employee of an armed force, said that a projectile fired upwards the impact with my body it hurts less than when it drops downwards.
In my opinion all this ...
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1answer
39 views
No friction in pure rolling - how about driving a car?
I remember the un-intuitive result that pure rolling without acceleration involves no friction by the law of conservation of angular momentum. Conjectures:
I understand that when I'm driving a car at ...
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Thrust needed from an engine to reach orbit
Assume you had an airplane with magical engines that didn't need fuel, air or power, to operate. What thrust to ground weight ratio would the airplane need to reach orbit? By ground weight I mean mass ...
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2answers
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Why are golf balls the only (famous) object with dimples?
To my knowledge there isn't anything that uses dimples to reduce drag. It's weird to hear why dimples are useful and help the ball go farther while at the same time finding no other examples.
I ...
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2answers
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Did Usain Bolt really sustain 11 horsepower of exerted power during the 100 m sprint?
I've just come across a WP article which says: "The Jamaican sprinter Usain Bolt produced a maximum of 3.5 hp (2.6 kW) 0.89 seconds into his 9.58 second 100-metre (109.4 yd) dash"
Out of curiosity, I ...
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2answers
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Which way would objects, inside a container falling through earth's atmosphere, move, relative to the container?
Say, a sealed hollow container with 1 atm air pressure inside, is falling through earth's atmosphere.
It is falling steadily with one side always facing the ground (Front Side)
Inside the container, ...
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2answers
18 views
Aerodynamic Force Decomposition
We know that aerodynamic drag is proportional to the square of the velocity of the incoming flow: $$D=kV^2.$$
If I decompose velocity into arbitrary orthogonal $x$-$y$ directions:$$V_x=V\cos\theta\\...
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2answers
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With drag, why does it take longer for an object thrown upwards to fall back down than it does for it to reach its highest point? [duplicate]
Why does it take longer for an object thrown upwards to fall back down than it does for it to reach its highest point? We can draw a free body diagram for when the object is falling down and for when ...
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1answer
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How to calculate air resistance? [closed]
What is the best way to calculate or take into account air resistance?
I have an assignment which goes as:
Drop an object by itself and with a parachute, calculate air resistance for the parachute. ...
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Does the Choice of Coordinate System Matter for a Particle Falling Downwards in a Linear Medium
I have a question regarding John Taylor's treatment of a particle falling down in a medium that exerts a linear drag force (Chapter 2 of his book "Classical Mechanics").First some background, he ...
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4answers
291 views
What is the reason terminal velocity changes with radius?
I know that terminal velocity equals to some multiple of radius square. What is the physics behind this relationship. Is it just because as terminal velocity increases, the surface area increases and ...
