Altitude Definition and 250 Threads

As we go higher up a mountain, the air pressure decreases. But why would that cause the air density to decrease? Since pressure is hpg, so if h decreases pressure decreases but what causes the air density to decrease as well? Thanks for the help :)

Homework Statement How fast must a satellite 10,000 miles above Earth's surface travel, and how long does it take to complete one orbit of Earth? Homework Equations v^2 = g*r The Attempt at a Solution 10,000 miles + radius of Earth = 14,000mi = v^2 = (9.8)(2.253*10^7m)...

Homework Statement The modern Boeing 747 passenger jet airplane cruises at a speed up to 920 km/hr, at an altitude of 11,500 m. The cabin pressure is maintained equivalent to the atmospheric pressure at an altitude of 2,000 m. This is called the "cabin altitude". I couldn't find information...

Hi! Just got a question from my 6 years old nephew who just traveled in an aeroplane for the first time. He wonders where (which altitude) the heaven turns in black? Someone who knows?

Some of the Aircraft Flight Manuals I have contain a "Cabin Altitude for Various Airplane Altitudes" graph in them. Typically, the Aircraft Altitude is on the y-axis, going from 0 to about 50,000 feet; and the Cabin Altitude is on the x-axis. Then there are a series of diagonal lines on the...

A cruise missile, small--say 10 feet long, making 4000 mph at 1 mile altitude- Would it make a boom loud enough to break windows? The smaller the craft, the less the boom, correct? Probably would be a tough one to answer; no aircraft I'm aware of is that small, making that kind of speed. The...

Hi, Assume an aircraft starts flying to east with zero pitch and roll, would this aircraft slowly move away from Earth surface due to Earth being a sphere ? Or would changing gravity direction or some other factor cause this aircraft to fly an arc like path which is parallel to underlying...

Homework Statement Calculate the pressure at this altitude. Assume a US standard atmosphere. an air parcel rises from sea level, where the pressure is 1.01 × 10^5Pa, to an altitude of 2.0 km. A.calculate the pressure at this altitude. Assume a US standard atmosphere, take the air to be dry and...

Aerocapture: Aerodynamics OR Aerodynamic Heating OR High-Altitude Atmospheric Model I apologize for the many topics covered at once here, but, this is why: I'm trying to design a vehicle to make aerocaptures from Earth to Mars, and from Mars to Earth (I do these kinds of things quiet a lot...

Homework Statement a rocket is launched at an angle of 53 degrees above the horizontal with an initial speed of 100 m/s. the rocket moves for 3 s along its initial straight line of motion with an acceleration of 30m/s^2. FInd the max altitude reached by the rocket Homework Equations y=y0...

1. A plane has a velocity of 280 m/s at an angle θ below the horizontal. When the altitude of the aircraft is 2.15km, it releases a water bomb, which subsequently hits a target on the ground. The magnitude of the displacement from the point of release of the bomb to the target is 3.25km. Find...

Homework Statement I am trying to figure out how to calculate the temperature at any given altitude in the troposphere. Homework Equations Let P=air pressure, V=volume of air above a given altitude, n=number of moles of gas, R=the ideal gas constant, T=temperature, and h=height above sea...

Relevant equation: PV = nRT Attempt: P1/P2 * V1 / V2 = T1/T2 V1/V2 = 4.2E12 / (1E12 - (6371.5 + h^3)

Homework Statement A rocket of mass 1.5 x 10^6 kg is launched upward from the surface of the Earth (mass ME = 5.97 x 10^24 kg, radius RE = 6.38 x 10^6 m) with a speed of 0.5 x 10^4 m/s. The rocket will reach a maximum altitude above the surface of the Earth of Homework Equations I...

I am trying to develop a spreadsheet to calculate a convection coefficient with altitude as one of the inputs. What variables should I consider? The most obvious are pressure and temperature, but I'm sure there is more to it than that.

Would anyone know what altitude would be needed within a vacuum in Earth's gravity to create an impact of 4kg using a weight of 70g? Thanks

Hard to find a suitable title, but I have a simple question about electric charce and how a generator is affected by how high up one of the charged plates are: If I want to charge two plates with +/- 100kV, then electrons are forced from one plate to the other, so one plate is positive, and...

An observer on Earth sees a meteor approaching rapidly, heading directly for the Earth's surface. At a certain instant, the Earth observer sees the meteor at 650m altitude. If the meteor is traveling at 0.92c, as recorded by an Earth radar, what would be the altitude as measured by the alien...

Bernoulli's principal states that as velocity of a fluid increases, the static pressure decreases. I wonder if the reverse order can also happen. For example, if there is a pipe laid on the side of a mountain that is 3000 ft high. The bottom end of the pipe would be exposed to pressure at sea...

Is temperature "different" at altitude? I know the boiling point of water is lower at higher altitude. But a friend of mine says that temperature in general is different at altitude. So, if the cooking instructions say to bake something at 425, he says you should set the temperature of the oven...

At what altitude does a solar panel see a noticeable increase in wattage/cubic meter if it is lifted into the air? I understand the maximum is a bit over 1 kilowatt/meter2 at sea level (not actually converted to usable energy, this is much less and depends on the technology) but that this...

I have read some threads on this topic, but I am still confused. Why does temperature drop as you go up a mountain? I have read that since pressure depends on the weight of the air on top of you and as you increase your altitude the amount of air over you decreases, therefore pressure decreases...

Alright guys, just looking for a point in the right direction for a tutorial question. GIVEN VALUES: Temperature change with increasing altitude: 0.0065 K/m Temp at sea level: 15ºC Pressure at sea level: 101.5 kPa FIND: Atmospheric pressure at 7500m. So what I've done is found the...

Hi, Is anyone able to explain to me how i take a required altitude and calculate the required pitch rate from it ? Or a very simple tutorial on the process ? Thanks in advance Regards Mike

hes attempting to break a record for the highest free fall (37km from the Earth's surface) heres a link to a site about Joe Kittinger (who holds the current record at 31.3km) http://testblog-testblog123456-testblog.blogspot.in/2011/11/dispatches-blog-supersonic-man-col-joe.html

Homework Statement This is only part of the problem but this is all I'm having trouble with... Which effect of damping would be more noticeable, the change of period or the decrease of the amplitude? Homework Equations x(t)= Ae^{-\beta t} * cos(w_{1}t - \delta) period = \frac{2Pi}{w_{1}}...

Homework Statement The U-2 was an American spy plane capable of flying up to 21 km high at speeds over 600km/h. Determine the time required for the missile to reach its maximum altitude of the U-2. Homework Equations d=v_i t+1/2 at^2 The Attempt at a Solution d=21000m a=-9.81m/s^2 v_i=0 t=...

Hi I have been reading a lot about how to calculate gas density and I am stumped. What I would like to know is how to calculate the gas density as apposed to altitude so I can use it in the terminal velocity equation found here http://www.grc.nasa.gov/WWW/k-12/airplane/termv.html I would like...

Can you explain why we can have hot beverages at really high altitude don't stay hot? Why can't they have a nice pot of tea on mount everest?

Hey PFers. I'm just wondering what your thoughts on a High Altitude Telescope are. What I mean is pretty much a telescope on a platform suspended in air on balloons at 40,000+ feet. The whole thing would be solar powered, with a couple of engines capable of station keeping, with the appropriate...

Homework Statement You are a tourist on space odyssey; at what altitude above the surface of Earth will your weight be one-half your weight on the surface? express your answer as a mutiple of Earth's radius rE Homework Equations Fg= GMm/r^2 The Attempt at a Solution not sure how to...

Homework Statement How much energy is required to move a 1 000-kg object from the Earth’s surface to an altitude twice the Earth’s radius? Homework Equations U = - G Me m / r The Attempt at a Solution I'm just using the above equation with 2r (twice the radius) and get 3.1 x...

As a first year aerospace engineer student I had a problem today. The question was : Does the altitude effect the endurance of an aircraft (provided that the aircraft engines can generate enough trust at this higher altitude). Maximum endurance is minimum fuel flow [N/s] F = Ct T in a...

Homework Statement We have 2 model rockets identical in all ways (weight, height, mass, propellant, etc). The first rocket is launched like most rockets (0 ft/sec) and reaches 1000ft. For the second rocket we use a SUPER rubberband launch system. The launch system sends the rocket to say, 150...

Homework Statement [EDIT: My first statement of the problem was wrong.] 1. The space shuttle releases a satellite into a circular orbit 720 km above the Earth. How fast must the shuttle be moving (relative to Earth) when the release occurs?Homework Equations F=GmM/r^2 Fc = mv^2/rThe Attempt...

Hi, I'd like to know how it's possible to calculate the altitude of a satellite using some kind sensor. I know that near-space(28~30km) you can still read a very low pressure so I can calculate the altitude using pressure. But and after this? I read that you can use gravity so, can I use...

Sorry if this is in the wrong category but I had an exam question today that I couldn't figure out. The problem states that at an altitude of of 9600m the air pressure is measured to be 25 kPa. The question is what is the pressure at sea level? I feel like to answer this question you...

water has a density of 62.4lbm/ft^3 .How much does 2ft^3 of water weight at sea level and in Colorado where the altitude is 5374ft and the gravitational acceleration is 32.139ft/s^2? Solution : density=mass/volume 62.4lbm/ft^3=mass/2ft^3 mass=124.8lbm w=mg =124.8lbm*32.174ft/s^2...

Howdy, I am looking to find the rate of ascent for a weather balloon filled with helium. My assumptions as of now are total payload weight=10lbs, total balloon weight=2lbs, total balloon volume(at launch)=150ft^3, balloon diameter(at launch)=6ft. Also, how does the rate of ascent change with...

Homework Statement A rocket is red vertically with an acceleration of 250 m/s2. After 30 seconds, the rocket's motor shuts o. Find the maximum altitude achieved by the rocket and the total time from take-o to return to the surface of the earth, assuming that the rocket's design makes...

[b]1. Homework Statement [/ The value of acceleration due to gravity (g) at an altitude (h) is gh = g (1 - 2h/R). Similarly the value of g at a depth (d) is gd = g(1 - d/R), where R is the radius of the earth. Homework Equations In both the cases, my book says the value of g decreases...

Can someone explain how and why stall speed (TAS?) varies with aircraft weight and altitude? If you need equations to explain this, I can still handle algebra, but I have forgotten all of my college calculus! Thanks.

Hello, I have moved that question around in my mind for quite a while now. I have gotten several datasets from amateur high altitude balloon flights in which the Geiger Counters onboard delivered either no data or excessive count rates, and this occurred almost every time when a balloon...

Let's say, a missile fired from ground level is limited in range by aerodynamic and drag factors upto 3 kms. So how would that range be altered if the missile is fired from an altitude of 5 kms above mean sea level? What are the factors we need to take into consideration to calculate its range...

Here's a problem from an astronomy book "the top of the mountain 1000 m in height can just be visible seen from a ship approaching the land where the mountain is situated. . If the observer's eye is 30 m above sea level. Then how far the ship is from the mountain? " The main problem is i...

[b]1. a rocket is launched from rest and moves in a straight line at 70degree above the horizontal with an acceleration of 46ms^(-2) . After 30seconds of powered flight , the engines shut off and the rocket follows a parabolic path back to earth. find 1)the maximun altitude reached...

What would be the cheapest option to measure the altitude of a near space balloon? I know GPS can't be used because it is restricted to work below a certain point.

hi I'm new here and i need some help regarding atmospheric pressures. i have a way of calculating it up until about 50 km above sea level. is there a way to accurately model the pressure at an altitude up to 300km?

The Problem: A 4.60 kg rocket is launched directly upward from Earth at 9.00 km/s What altitude above the Earth's surface does the rocket reach? Relevant Equations: v = √ (2GM/r) The Attempt: m = 4.60 kg v = 9km/s = 9000m/s G = 6.67 x 10^-11 9000^2 = 2(6.67^-11)(4.60)/r...

Hello, I am struggling with understanding air temperatures effect on density altitude and it's effect on the flight of a bullet. I understand that as temp goes up air resistance/density goes down but in looking at a chart I have I can’t seem to make out a pattern in relation to temp. It...