Air resistance Definition and 405 Threads

Fluid Dynamics - Calculating air resistance on air Homework Statement I'm trying to figure out how much the velocity of wind will decrease by over a given distance. I know the velocity at a point 1cm after it has passed over an object, and i need to determine the velocity at the object...

Homework Statement The projectile with initial velocity v_0 is moving in environment with air resistance, which is linear to projectile's velocity. The task is to prove, that horizontal distance is maximal, if the elevation angle (\alpha) and the angle of trajectory tangent in place of impact...

Hello everyone. I've got a question that has been bugging me ... Do bodies have speed limit here on earth? Like cars, why do they have speed limits? is it because they are made this way for safety or is it because air resistance increases as speed increases? Not only cars but all...

Homework Statement 71. A paratrooper fell 370 m after jumping from an aircraft without his parachute opening. He landed in a snowbank, creating a crater 1.1 m deep. Assuming the paratrooper's mass was 80 kg and his terminal velocity was 30 m/s, estimate : a) the work done by the snow in...

A car of mass 1500 kg goes down a hill with a height of 50m. when the car reaches the bottom of the hill the speed is 15 m/s. how much energy was lost due to friction and air resistance? hey, I am having trouble with my home work T.T I have no clue how to do it if someone can help, much would...

Homework Statement An 84 kg person is parachuting and experiencing a downward acceleration of 3.0 m/s2. The mass of the parachute is 5.5 kg. a) What upward force is exerted on the open parachute by the air? (b) What downward force is exerted by the person on the parachute? Homework...

Homework Statement Consider a projectile without air resistance. Show that when the range is maximized, it may be given in terms of the maximum height Homework Equations R = 4hmax The Attempt at a Solution I tried looking upon the equation for the vector R but could not...

Ok so i have the distance traveled of an object assuming air ressistance is 0 and the distance traveled with air resistance included as well as the acceleration of the object, how would i calculate the coefficient of air resistance? Thanks

So, I've been having a bit of an argument with a guy about falling, identical items, with varying masses. Homework Statement For the sake of the argument, we've been using the example of two identical jugs, one filled with water, and the other without. They are dropped at exactly the same...

Hey guys, I have been working on some calculations to help me with sniping in airsoft. I am working figuring out the angle of inclination I would need to hit targets at different ranges being only a rough outline (I am not too worried about getting into the various calculations such as for air...

my techer didnt finish going through everything and she wants us to teach it to ourselves and i don't understand so please help. neglecting air resistance, the initial horizontal velocity of a projectile is ______ its final horizontal velocity is it ... greater than less than equal to...

Homework Statement Hey guys, I'm doing a problem on quadratic drag and energy dissipation. Basically, the question asks me to find the energy dissipated when a ball of mass 'm' is thrown directly upwards with a velocity 'v0', during the upwards journey to its maximum height, 'h'. The resistive...

1. Homework Statement An object is thrown horizontally from the top of a cliff at a velocity of 20m/s. If the object takes 4.20s to reach the ground, what is the range of the object? I got the first question figured out, but i can't figure out the second question which is: What is the...

Homework Statement An object is thrown horizontally from the top of a cliff at a velocity of 20m/s. If the object takes 4.20s to reach the ground, what is the range of the object? I got the first question figured out, but i can't figure out the second question which is: What is the velocity...

Homework Statement I'm trying to find the acceleration due to air resistance in x direction and acceleration due to air resistance +gravity in y component. given variables m-0.14273(baseball) Cd=0.4 Vi=20m/s angle= 45 degrees Basically, I have to program a projectile motion program...

Homework Statement I'm trying to program a projectile motion program for my physics project. We are suppose to take account effects on air resistnace If our drag coefficient is 0.4 our mass is 0.14273kg(baseball) initial velocity is 20, and angle is 45. What would be the acceleration of x...

[NEED HELP+DIAGRAM INCLUDED]Question about Air Resistance http://img410.imageshack.us/img410/3732/airr.jpg Red line- No air resistance Blue line-Air resistance present Ok, so I thought on the way UP, resistive forces (oppose motion) acts in same way as g-force => Deceleration is very...

Homework Statement a .459kg raindrop falls vertically at constant speed under the influence of gravity and air resistance. acceleration due to gravity is 9.8 m/s after the drop 141 m, the work done by gravity is 634.246 J a problem ask the work donde by air resistance the work done by...

How can i sketch a graph of velocity vs time for an object falling from rest taking into account air resistance. Will it be a curve ? How can i do it?

Homework Statement A 72 kg person escapes from a burning building by jumping from a window 30 m above a catching net. The acceleration of gravity is 9.81 m/s2. Assuming that air resistance is simply a constant 88 N force on the person during the fall, determine the person’s velocity just...

I don't know much about air resistance but i would like to learn. Basically all i know is that you assume a basic Taylor expansion and then (for some reason unknown to me) you drop out all terms other then the linear and quadratic ones. Both terms in the equation are velocity dependent...

Homework Statement Ok I am working on a spreadsheet that calculates the velocity/position/drag of a point-mass projectile and I have been digging up the same equations for days and they aren't helping... lol... I just can't seem to get the numbers right, any help would be greatly appreciated...

**Edit: Solved the problem, need help with some of the concepts though..[/color] Homework Statement The diagram shows a cart on a ramp which is fixed to the floor in the back of a truck. Friction in the wheels is negligible. At what rate must the truck accelerate forward for the cart to...

Q1: Assuming friction force to be negligibly small, what will be the acceleration in m/s^2 of a 45kg skater when propelled by a force of 250N? My attempt Data: F-250N m-45kg a-m/s^2 Formula: F=ma a=F/m a=250N/45kg a=5.555 a=5.6m/s^2 Q2: a 0.5kg mass on a horizontal frictional free...

A fire helicopter carries a 625 kg empty water bucket at the end of a cable 18.3 m long. As the aircraft flies back from a fire at a constant speed of 35.4 m/s, the cable makes an angle of 36.3° with respect to the vertical. Calculate the force of air resistance on the bucket.

Homework Statement A fire helicopter carries a 564 kg bucket of water at the end of a 19.2 m long cable. Flying back from a fire at a constant speed of 41.6 m/s, the cable makes an angle of 46.0° with respect to the vertical. Determine the force of air resistance on the bucket. Knowns: m...

Homework Statement the effect of air resistance is to slow down a moving object. It can be shown that height of a falling object is given by the following Homework Equations y=y0-[t+(e^-bt - 1)/b]g/b a. show that for short times this reduces to the expected expression y=y0-1/2gt^2...

Does air temperature affect air resistance? you have two similar balls, you failed them at the same time in two plate, one of them with 60Co and the other with 30Co, which one will reach first? http://up2.up-images.com/up//uploads2/images/hosting-1067f93ac6.jpg

calculating workdone due to friction and air resistance...HELP! Homework Statement this is my 1st post and i don't really no if i should put the whole question, so i will...just to make sure i get some help! A skier of mass 72kg, initially at rest, reached a speed of 32ms/1 at the bottom of...

Homework Statement A mass m is dropped from a height H onto a hard, flat surface. When it collides with the surface, it rebounds with the same speed it had before the collision. However, there is a constant force of air resistance f acting on the mass as it undergoes this motion. Answer the...

Hello, I am interested in the problem of air resistance on a cylinder rotating about its axis (axis of rotation is through the flat parts). I used the drag equation and substituted the "cross-sectional" area as the area that's rotating at R (if R is the radius of the cylinder) so it would be...

Homework Statement A vehicle of mass m experiences a constant frictional resistance ma and air resistance proportional to the square of its speed. It can exert a constant propelling force mb and attain a maximum speed V Show that, starting from rest, it can attain the speed V/2 in the time...

Homework Statement As a bonus question on an assignment for my advanced physics class, we were asked to calculate (approx.) the expected time to impact of a drop of water falling 412m, from a tall building to the ground, considering linear drag. I've done most of the calculations but I expect...

im very interested to find out. iv been trying to nut it out but as of yet have not really got anywhere and so i thought id ask the brains here at physicsforums. btw i realize direction changes but does the magnitude of air resitance change? i was assuming it didnt but if i did I am just...

Homework Statement The effect of air resistance is to slow down an object. It can be shown that the height of a falling object is given by the following: y=y_{o} - [t + (e^{-bt} - 1) / b] * g/b. Show that for short times the eqn is reduced to y=y_{o} - 0.5(g)(t^2) Homework...

Homework Statement A baseball of mass 0.145kg and radius 0.0366m is dropped from a tower 381m high. Homework Equations The Attempt at a Solution Work=integral(from 0 to 381): c(2) (terminal velocity)^3*(tanh(t/(characteristic time)))^3 with respect to time. Gets me really...

Homework Statement The question asks me to work out the coefficient of friction for a block accelerating down a rough slope assuming their is no air resistance, which I could do easily. In the next part it then asks how the coefficient would change if their was air resistance Homework...

Homework Statement Consider a ball which is projected horizontally with speed u from the edge of a cliff of height H as shown in the Fig. (1). There is air resistance proportional to the velocity in both x and y direction i.e. the motion in the x (y) direction has air resistance given by the...

I have a question to ask. Imagine a ball being thrown upwards with a certain initial velocity. Neglecting air resistance, let the total time for the ball to reach its maximum height and back to its original position be T. With the presence of air resistance, will the total time be any different...

Homework Statement A sphere of radius 0.2 cm is fired straight up with speed v0. What is its speed when it hits the ground? (Include quadratic air resistance but ignore linear air resistance.)Homework Equations Quadratic air resistance: FR = cv2 c = 0.5CpA = 4.05 x 10-6The Attempt at a...

Hey all, I'm new to this forums. My question is this, I've been learning about projectiles and I came across a thought regarding air resistance. For example if you have a more massive object (more kg) does it fall less distance(range) because of the addition of vectors of mg(weight force which...

Me and my friend were traveling in the car and started thinking. Say your traveling 60 mph north and there was a head wind traveling 60 mph north. When you stick your hand out the window, do you feel air resistance? Thanks for your response, Rob

Could anyone please explain to me how to work the following question out? A table-tennis ball of mass 10g is falling towards the ground with a constant speed of 8.2m/s. Calculate the magnitude and direction of the air resistance force acting on the ball.

Hello, Why are helicopter blades put on top of the aircraft? Doesnt the air pushed down from the blades push down on the helicopter? Wouldnt it make more sense to have the blades on the bottom?

Calculating effects of air resistance on a ball of mass 0.67kg, being dropped from a height of 4.93m. I have worked out theoretically what time it would take without air resistance using s=ut + 0.5at(squared) however i cannot find an equation that will factor in air resistance. thanks

How do you add air resistance to these 2 equations? #1 sqrt(2 * d / g) = time until impact #2 sqrt(2 * d * g) = velocity on impact The equation for air resistance is: Fd = 0.5 * Air Density * Velocity ^2 * Frontal Area * Drag Coefficient How would you combine this equation with the above...

I'm trying to calculate the torque i would need to pedal when in the highest gear on my bike to sustain a constant speed on level ground. Basically i just want someone to review my calculations and make sure they're correct. I leg press 270 pounds and therefore each of my legs can supply 135...

I'm having a little trouble calculating the force of air resistance for a bicycle. The formula I used is: Fd=1/2pv^2ACd . p= 1.3kg/m^3 v= 13.44 meters/sec. A= 1.15 meters^2 Cd= 0.9 I got an answer, but I don't know if it is correct, can someone please verify?I got 121.52 Newtons.

Having this discussion on another board, basically stemmed from one member saying that a bullet would be in flight for "over 5 seconds"in response to something else someone said about a 0.50 caliber sniper rifle firing at a target 2 miles away. I figured that negating air resistance, the time...

Homework Statement A table tennis ball of mass 10 g is falling towards the ground with a constant speed of 8.2 m/s. Calculate the magnitude and direction of the air resistance force acting on the ball. Homework Equations Not quite sure The Attempt at a Solution m= 10 g which...