What is Air resistance: Definition and 415 Discussions
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, drag force depends on velocity.Drag force is proportional to the velocity for a laminar flow and the squared velocity for a turbulent flow. Even though the ultimate cause of a drag is viscous friction, the turbulent drag is independent of viscosity.Drag forces always decrease fluid velocity relative to the solid object in the fluid's path.
if we lunch a projectile with the act of air resistance which t (time) is longer
t1 =>from t=0 to arriving to the highest point
t2=> from highest point to the lanch point
Homework Statement
Ignoring air resistance is a large error when dealing with cars, especially when they are traveling at high speeds. Remember that air resistance depends on the speed squared F_ar=-Av^2.
A) draw a "FBD" for the car. show that the power required to keep a car going at a...
Homework Statement
A body of mass m is dropped from a certain height without initial velocity. At the time t when its speed is v, what is the work done by the air resistance to retard the body?
Homework Equations
Laws of conservation of momentum and inertia
The Attempt at a Solution...
I need to compute the time of flight of a projectile which is subject to air resistance.
Here's where I am so far in solving the problem:
F_{drag} = -B v^2
a = \frac{\partial v}{\partial t} = \frac{-B v^2}{m}
integrate and solve for v...
v = \sqrt[3]{\dfrac{1}{3 \dfrac{B}{m} t + C}}
I then...
i have solved the question of a pebble thrown upwards without air resistance
speed 10m/s mass 0.02kg ma=w, w=-mg
man on cliff 50 feet high throws pebble upwards so it finishes in sea,
what height does it reach v=0 t = 10/g approx =1
since motion started at t =0 & duration of time 1s...
If anyone could help with the following, it would be great.
I am currently carrying out an experiment for a school project to see how damping affects and reduces the amplitude of the oscillation of a pendulum. For the pendulum I am using a suspended metre ruler and I will count the number of...
Please, any help would be appreciated.
Air resistance is a force that acts in the direction opposite to the motion and increases in magnitude as velocity increases, let us assume at least initially that air resistance r is proportional to the velocity: r = pv, where p is a negative constant...
Air resistance is a force that acts in the direction opposite to the motion and increases in magnitude as velocity increases, let us assume at least initially that air resistance r is proportional to the velocity: r = pv, where p is a negative constant. suppose a ball of mass m is thrown upward...
a friend of mine asked if i could help him work out some equations for a (fairly) long range projectile, to go no farther than 2 miles or so. i have everything reasonably worked out except for acceleration due to air resistance. I'm using the equation from...
Problem:
A rocket is launched vertically upward. The rocket has a mass Mr and carries Mo of fuel. The fuel burns at a constant rate (ß) and leaves the rocket at speed Ve relative to the rocket. Assume constant gravity (9.8m/sec^2). There is an air resistance given by F(a) = -kV.
Where V is the...
[b]1. a 150 pound person on a snowboard launches off a 45 degree angle jump at 12 feet per second. what is the peak hight, flight time, horizontal displacment, and vertical displacement.
[b]3. i tryed to use kinimatic equations to determine all the variables but all were way off[WAY off]. i...
Homework Statement
An airplane pilot fell 370 m after jumping without his parachute opening. He landed in a snowbank, creating a crater 1.1 m deep, but survived with only minor injuries. Assuming the pilot's mass was 80 kg and his terminal velocity was 50 m/s, estimate: (a) the work done by...
Hi,
I'm trying to model air resistance to try and predict where destroyer gun shells will land on an online computer game. I've tried quite a few things which have met with some success but are not accurate enough. I think however this time I might have found a better solution in the form of...
I am trying to plot the trajectory of a projectile. I found formulas for finding the drag force, but it only gives me the drag force at an impossibly short interval of time, i need it to affect the trajectory of the projectile threw out it's path. The projectile is also affected by gravity. If...
Homework Statement
Human reaction time is usually about .20s. If your lab partner holds a ruler between your fingers and thumb and releases it without warning, how far can you expect the ruler to fall before you catch it. (disregard air resistance g= 9.81 m/s^2)
Homework Equations...
Homework Statement
I'm currently working on a lab which involves swinging a bung in the horizontal plane (just like a conical pendulum), however I'm a bit stumped at finding air resistance.
The variables we know are the radius, the centripetal force and the velocity of the bung.
The...
Hi guys, got a question and been trying to solve it for 2 days.
the question is:
In the absence of air resistance with what angle to a horizontal ground must an object be thrown from ground level so that it ravels a distance before landing equal to twice the maximum height ?
I know...
My class did a lab where we roll a cylinder down a ramp (the end of the ramp was at the edge of the table). We placed a photogate timer right at the position where the cylinder fell off the ramp, and a photogate timer right at the position where the cylinder hit the floor.
The information...
If you jumped out a plane, you would begin speeding up as you fall downward. Eventually, due to wind resistance, your velocity would become constant with time. After this occurs, the wind resistance force’s magnitude is
a.much smaller that the gravitational force acting on you.
b.slightly...
QUICK: Work And Energy Problem Involving Air Resistance
a projectile mass of 0.750 kg is shot straight up with an intial speed of 18.0 m/s. (a) how high would it go if there were no friction? (b) if the projectile rises to a max height of only 11.8 m, determine the magnitude of the avg force...
i know this has to do with air resistance but what is the equation for it so i could use it for this problem?
The Steamboat Geyser in Yellowstone National Park, Wyoming is capable of shooting its hot water up from the ground with a speed of 48.0m/s. How high can this geyser shoot?
A 1.21 g samara--the winged fruit of a maple tree--falls toward the ground with a constant speed of 1.1 m/s What is the force of air resistance exerted on the samara?
I know that F=ma
I also know I have to account for 9.81 N for g. So by upward force am I looking for W? That would be 11.9N.
i am doing my hoem work and this question is confusing the hell outta me.
A 4.35 * 10^-5kg raindrop falls vertically at constant speed under the influence of gravity and air resistance. After the drop has fallen 76m, what is the work done by gravity? After J is found for gravity, what is the...
Hey. Just a random though. Why does the force of air resistance increase for say...a freefalling body..as its velocity increases? Is it because it encounters more air particles to which it must overcome?
Thanks,
Dan.
Hey there, I have been studying for my physics final coming up and I am constantly getting stuck on the stuff that we started at the beggining of the year. Such as this question:
A 6 kg object is projected directly upwards with an initial speed of 15 m/s. This object experiences an average...
A paticle of mass m is projected vertically upwards with speed U. The air resistance produces a retarding force mkv^2 , where k constant and v the speed of the particle. Find the greatest height reached by the particle. Determine the speed W with which the particle will return to the point of...
I'm in a high school AP physics class but I suspect this question is considerably above the course level because I don't think it was intended to be a part of the project, so I'm not sure which forum to put it in.
I would like to find the initial velocity required to launch a ping pong ball 25...
My maths teacher before we broke up for christmas asked the class to work out a simple model for air resistance for an object that is dropped given that the resistive force is proportional to the square of the velocity. I've spent about 10 minutes thinking about it, and this is what I came up...
The Air Resistance of a car grows proportional to the square of the velocity. On a certain car is the air resistance 0,18kN when the velocity is 54km/h.
So the problem is ..
What is the air resistance when the velocity is 90 km/h?
How high is the velocity when the air resistance is...
If a free-falling body is not subject to air resistance, there is a linear relationship between v and t giving a line with constant slope (g) showing velocity increasing with time.
If air resistance is taken into account, my guess is that acceleration will decrease until the terminal velocity...
Hi, I'm having problems with this question:
ok first I determined what work that gravtity does which is m*g*(delta y) which in this case is -50 J
I then used the CEW theorem equation using the velocities to find the total work done: (sigma W) = 1/2 m (v^2 (final) - v^2(initial)) which is...
So, here's the question:
The speed of falling rain is the same 10m above ground as it is just before it hits the ground. What does this tell you about whether or not rain encounters air resistance?
So here's my attempt:
Since the speed of the falling rain is just the same 10m above ground...
Need urgent help -- projectile motion with air resistance
Consider a projectile fired vertically in a constant gravitational field. For the same inital velocities, compare the times required for the projectile to reach its maximum height (a) for zero resisting force and (b) for a resisting...
Projectile Motion with air resistance -- need urgent help
Consider a projectile fired vertically in a constant gravitational field. For the same inital velocities, compare the times required for the projectile to reach its maximum height (a) for zero resisting force and (b) for a resisting...
Ok, in this problem, only the y direction is dealt with
Here is the problem
You are standing on top of a building, 30 m above the ground. You throw a ball (m = 0.15 kg) with an initial velocity or 20 m/s (in the y direction). Air resistance is given as (1/30)*v (yet again only considering...
Hello All,
I was recently intrigued by the site: http://www.lcse.umn.edu/specs/labs/catapult/ which sets about showing a computational solution to the problem of projectile motion with air resistance. I think the site is a great idea, and presented well, but it seems like some of the physics...
"A particle is relased from rest (y = 0)and falls under the influence of gravity and air resistance. Find the relationship between v and the distance of falling y when the air resistance is equal to a) av and b) Bv^2."
I already solved part a by integrating dv/dt = -g - (a/m)(dy/dt) with...
Air Resistance & Horizontal Distance
Warning: Calculus Required
This was a discussion question in my class's Young & Freedman University Physics book. Page 150, Chapter 5, #29.
Q5-29 When a batted baseball (kicked football, whatever floats your boat, assume the initial vertical position...
What equation represents the force of air resistance? Is it simply \vec F_{air} = c \vec v , or must the velocity be raised to a higher power?
*Also, which equation represents wind resistance to an object, in the case where a wind is blowing relative to the ground ?
Mathematically, how would air resistance affect trajectory?
Suppose I shoot a cannonball with initial velocity v_0 at an angle of elevation \theta . Air resistance is a force antiparallel to velocity, represented by the equation (according to Barron's Physics C review book!) \vec F_{air} =...
Take a look at this little web-progarm
http://galileo.phys.virginia.edu/classes/109N/more_stuff/Applets/ProjectileMotion/jarapplet.html
I know that it uses the following equation to calculate the range of the projectile without air resistance
R = (v^2 sin2(theta))/g
R - Range
v - intial...
My question deals with times of flight under a linear model of air resistance. Let me describe the problem.
Up problem: v' = -g - kv, x(0) = 0, v(0) = v_0
Down problem: v' = -g + kv, x(0) = h, v(0) = 0
Define T_{up} and h (max. height) by the Up problem: x(T_{up}) = h, v(T_{up}) = 0...
let's say i have a 5kg ball and i throw it up with an initial V of 30m/s with air resistance of 25, how would i find the work done by air resistance on the way up and on the way down?
A 22-cm-diameter bowling ball has a terminal speed of 85m/s. What is its mass.
I get F=M(9.8). But then i don't know where to go from there or what to do with the 22 cm diameter :confused:
Hey,
While searching for a solution to a particular problem, I stumbled upon this forum; any help would be greatly appreciated.
We're currently working on energy and power, and in spite of my past success with such problems, I couldn't solve this one:
A volleyball is dropped from a...
a small question, on the moon, the small amount of gravity prevents sudden falling like on earth, however would the lack of gases allow somebody jumping on the moon a much faster falling speed than on earth, because they do not have resistance from the electrons in usual earthly gases.
A 3.51 x 10^5 kg raindrop falls vertically at
constant speed under the influence of gravity
and air resistance.
The acceleration of gravity is 9.8 m/s^2 :
After the drop has fallen 115 m, what is the
work done by air resistance?
would it be opposite of that done by gravity which i found...
I'm doing a data handling course work project. I've calculated various values for resistance and found that resistance increases as the speed of the body increases. I know that as the body is rolling very little of the force is friction, so most of it will be air resistance. i have an idea...
Hi guys
I need help solving the following differential equation for air resistance
d^2s/dt^2 + R ds/dt = g
Where g = gravity I presume and R = k/m where k = resistance constant
Using my limited knowledge I think that the auxiliary equation for this is
Y^2+ RY = 0
Y = 0 or R...
hi ,
As a part of my project, i am modelling air resistance using a differential equation. For the write up, i need to discuss what assumptions i am making. I have the rest of the coursework sorted out.
I have a few idea .
Air resistance is presumed to be consistent. ( i.e no...