Question about gravitational acceleration

In summary, when playing with a calculator to calculate the g force on a disc that is spinning at 50,000 RPM, it is determined that a g force of 2795609.8954G can be achieved. This is much higher than the g force that is normally experienced on a middle-sized star.
  • #1
Crazymechanic
831
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not so good at math so please help me.When I play with those artificial gravity or should say centripetal force calculators I get some pretty big numbers so I need some verification of them.
Is it true that spinning a let's say 1m. radius disc with 50 000rpm/min you would get like 2795609.8954 g force on the side of the disc? And if so isn't that close or even over to that you normally would get on a middle sized star? Certainly bigger than our sun.?


How could I calculate the highest possible g force a specific flywheel or material or disc could withstand?

And the last thing a disc or whatever solid material rotating fast doesn't get very hot , well if we don't consider the air resistance and friction, but now let's imagine that around the disc is a chamber full with gas and we spin the disc very fast does the gas act similar as the solid or does the gas heat up differently?
 
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  • #2
F = ma..right?? and for a rotating object ...a = v2/r

the v is the tangential velocity so you'll have to convert 50,000 RPM to a velocity. Each revolution travels a distance of 1 circumference or C = 2[pi]r...and you'll have 50,000 of these each minute...
How could I calculate the highest possible g force a specific flywheel or material or disc could withstand?
not likely practical to calculate it...use an experimentally determined figure:

see

http://en.wikipedia.org/wiki/Tensile_strength
 
  • #3
If you look at

http://en.wikipedia.org/wiki/Flywheel_energy_storage

you can get some additional insights.

One observation is that the maximum energy density you can get is proportional to σ/ρ where σ is the tensile strength of the material and ρ is its density.

This means the the maximum tangential velocity is proportional to the square root of σ/ρ
And that means that the maximum rotation rate is roughly given by sqrt(σ/ρ)/r.
 
  • #4
Thanks for the answers , oh by the way can somebody answer the last part of my thread?

And the last thing a disc or whatever solid material rotating fast doesn't get very hot , well if we don't consider the air resistance and friction, but now let's imagine that around the disc is a chamber full with gas and we spin the disc very fast does the gas act similar as the solid or does the gas heat up differently?
 
  • #5
So F=ma mass let's say 5 tons and radius of the disc 10 meters. and "a" is like (assuming 50 000rpm) C = 2[pi]r that would be like 2x(3.14x10) == 2x 31.4=62.8
now a = v2/r that would mean a=62.8x62.8/10 is equal to 394.384

now the F=ma part. F=5000x 394.384= 19711920 (N)

I'm sorry for my abstract nonsense type of calculus but could someone verify that I did the calculations right?
And 19711920 N , how do I convert that to G ?

Thanks.
 
  • #6
Anyone? And yes could someone tell me about how does gas or plasma states react to tangential pressure compared with a solid material?
 

FAQ: Question about gravitational acceleration

What is gravitational acceleration?

Gravitational acceleration is a measure of the rate at which objects fall towards the Earth due to the force of gravity. It is denoted by the symbol "g" and has a value of approximately 9.8 meters per second squared near the Earth's surface.

How is gravitational acceleration calculated?

Gravitational acceleration is calculated using the formula g = Gm/r^2, where G is the gravitational constant, m is the mass of the object, and r is the distance between the object and the center of the Earth.

Does gravitational acceleration vary on different planets?

Yes, gravitational acceleration varies depending on the mass and radius of the planet. For example, the gravitational acceleration on Mars is only about 3.7 meters per second squared, while on Jupiter it is about 24.8 meters per second squared.

What factors affect gravitational acceleration?

The main factors that affect gravitational acceleration are the mass of the objects involved and the distance between them. The larger the mass and the smaller the distance, the stronger the gravitational acceleration will be.

How does gravitational acceleration affect the motion of objects?

Gravitational acceleration causes objects to accelerate towards the Earth at a constant rate. This acceleration is responsible for the motion of objects falling towards the Earth and the motion of planets orbiting around the sun.

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