We were wanting to look at information that one would need, in order to calculate how long it would take for the NASA UARS satellite to reach the earth's surface once it entered the atmosphere.
You can read more about satellites here http://www.nasa.gov/audience/forstudents/5-8/features/what-is-a-satellite-58.html
This concept was obviously "theoretically" only and was not be accurate in any way but its was project we decided to look at.
At the end of it we realised that we needed to learn more about the difference between speed, acceleration and velocity. There were also a couple of other things that we learnt.
At the end of it we realised that we needed to learn more about the difference between speed, acceleration and velocity. There were also a couple of other things that we learnt.
At first we thought that if we could get certain info such as mass, speed and distance, we could use one of the physics formulas we had learnt about to work this out.
We had a look at this website http://www.ucar.edu/learn/1_1_2_2t.htm How high does the atmosphere go? It turned out that each of the websites we looked had different measurements but we used the first one as it was only a theory we were looking at.
The info on the website, states that the "thickness" of the atmosphere (the distance between the earth's surface and the "top" of the atmosphere) is not an exact measure.
On this site they stated that the atmosphere is made up of 2 layers. The layer that is closest to the earth is the Troposphere (7 miles. The Upper layer of the atmosphere is called the Stratosphere (29 miles).
The approximate measure of the atmosphere is therefore 36 miles. (according to this website). We used this measurement.
(There is also info on http://www.enchantedlearning.com/subjects/astronomy/planets/earth/ which states "The Earth's atmosphere is about 300 miles (480 km) thick, but most of the Earth's atmosphere is within 10 miles (16 km) of the Earth's surface.") *but we had used the first info for our theory - no matter.
If we used the formula: Time = distance / velocity we considered that we could work out, theoretically, how long the satellite would take to reach the surface. Obviously there are many factors involved, including friction (burn up), gravity, rotation of the earth, path of the satellite etc.
We get the velocity from this website:
Time = distance / velocity
Time = 36 miles / 18000m/h
Time = 0.002 hours
To convert this we x by 3600s (1 hour)
Time = 7.2 seconds.
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(Is this the correct way to convert to seconds ? - I think it is)
This is a very short time but it does make some sort of sence, if you consider that when we think we see a falling star, it is actually only a piece of space debris or meteor etc entering the atmosphere. The time that a falling star takes is seconds as well!
Here is another site that again has different measurements and additional layers to the atmosphere. http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html. They list the layers of the atmosphere as Trophoshere , Stratosphere, Ionosphere and Mesosphere = 550km in total.
We also used these measurements in the same formula:
Time = distance / velocity
Time = 550km / 28968.19km per hour (18000m/h)
Time = 0.019 hours
To convert this we x by 3600s (1 hour)
Time = 68 seconds
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After this we looked at the NASA website for info on the atmosphere. Again it has different info and more layers, going upto 600km. http://www.nasa.gov/audience/forstudents/9-12/features/912_liftoff_atm.html This has the most info and presumably it is accurate as they have done a lot of research.
***One interesting thing we did find out BTW is that NASA are crashing this satellite intentionally! That's something to think about. We also learnt about orbital debris and how much there is in orbit.
***One interesting thing we did find out BTW is that NASA are crashing this satellite intentionally! That's something to think about. We also learnt about orbital debris and how much there is in orbit.
EXTRACT "Its orbit was been altered by Nasa deliberately to make it crash – but it is now coming down sooner than expected due to changed atmospheric conditions."
Read more: http://www.dailymail.co.uk/sciencetech/article-2040818/Satellite-falling-earth-1-3-200-chance-NASA-UARS-hit-person.html#ixzz1YnL4pVvX
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Next we looked at the formula
Next we looked at the formula
Force = mass x acceleration
We know the mass is 6 tonnes and 1 tonnes = 1000 kilograms therefore the satellite is 6000kg. This info of 6 tonnes comes from news reports and the NASA site. Acceleration is 18000 miles per hour. (Note: This figure of 18000 miles/hour comes for http://www.dailymail.co.uk/sciencetech/article-2040818/Satellite-falling-earth-1-3-200-chance-NASA-UARS-hit-person.html and other sites)
So Force = 6000kg x 18000 miles per hour
Force is measured in Newtons (N) therefore
Force = 108 000 000 N ??
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Alternatively if I convert the 18000 miles per hour to km/h, I get 28968.19km per hour. (I used this to convert miles to km http://www.calculateme.com/Speed/MilesperHour/ToKilometersperHour.htm)
My calculation for Force would then be = 6000kg x 28968.19km per hour
Force = 173 809 140 N
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In any event both answers are extreme amounts of Force!
Bear in mind, though that the satellite is set to burn up and break up the final force will differ. This is theoretical only. It would also make a difference to the answer in Newtons UK the unit of measure is m/h so how does this effect Newton
Its interesting to think about things....
I want to look more at the difference between speed, acceleration and velocity. They are both measured in m/s and km/h.... - depending on what system your country uses - what unit should you use for calculations?? As it gives different answers! Also want to look at the difference between weight and mass.
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Read this website to learn how satellites stay in orbit...http://library.thinkquest.org/C007258/Keep_Orbit.htm
It seems they travel a distance and fall closer to the earth during that travelling (like a ball when you throw it). Because the earth has constant curves the satellite does not actually fall into the earth. It just has constant movement around the earths curves. You have to read the article yourself to understand it.
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