Accepted value of G with longitude

In summary, the conversation discusses the accepted value of g needed for a lab write up and how to calculate it at a specific longitude. Suggestions are made for using 10ms^-2 and a link is provided for further information. It is also noted that the equation may need to be adjusted for local geology. The conversation then delves into a discussion about significant figures and provides an example using Newton's equation of gravitation to show the importance of handling significant figures carefully. The calculated mass corresponding to a 0.0000000001 m/s/s change in g is determined to be around 1.4985763 kg, which is equivalent to a large pebble.
  • #1
B-80
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Hey I have a lab write up due, and on it I need the accepted value of g and to get it at my longitude, any idea what this means, and how I can figure it out
 
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  • #2
Your longitude [by which, we'll pretend you actually said latitude]? Do you mean altitude, or do you have some experiment that can distinguish centripetal acceleration from gravitational acceleration (without being sensitive to geological variations specific to your location)?

I suggest "10ms^-2".
 
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  • #3
Here is a link:

http://geophysics.ou.edu/solid_earth/notes/potential/igf.htm
 
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  • #4
thanks man so its 9.7803267714 right? and then the other equation next to it with lambda is to fix for longitude?
 
  • #5
No lambda is latititude, there is no theoretical reason to fix for longitidue.
Note that the equation is an avaerage over the earth, after about the 3rd decimal place the local geology has a larger effect, so you probably don't want to quote more sig figures.
 
  • #6
Can someone knock up a quick example to show the OP how ridiculous the number of SF he has used there is?

What kind of mass corresponds to a 0.0000000001 m/s/s change in g? A pebble? A boulder?

It's something i'd be interested to know. And I think that it's important that the OP has it hammered home how carefully you have to handle SF.
 
  • #7
Using Newton's equation of gravitation g = -(Gm) / r^2

G = Gravitational Constant r = Distance from centre of body g = "Force" due to gravity m = mass

Assuming the radius of the object is 1 meter

0.0000000001 = (6.67300 × 10 ^ -11 x mass) / ( 1 ^ 2)

Mass = 0.0000000001 / 6.67300 × 10 ^ -11

Mass = 1.4985763 kg

So yeah a large pebble...
 

1. What is the accepted value of G with longitude?

The accepted value of G with longitude is the gravitational constant, which is a physical constant that represents the strength of the gravitational force between objects. It is typically denoted by the letter "G" and has a value of approximately 6.67 x 10^-11 N*m^2/kg^2.

2. How is the accepted value of G with longitude determined?

The accepted value of G with longitude is determined through various experiments and observations, such as measuring the acceleration of objects due to gravitational force, tracking the orbits of celestial bodies, and using sophisticated instruments like torsion balances and Cavendish apparatus. These experiments and observations are then analyzed and the accepted value is calculated based on the data collected.

3. Has the accepted value of G with longitude changed over time?

Yes, the accepted value of G with longitude has changed over time as more accurate measurements and advancements in technology have allowed for more precise calculations. In fact, the accepted value of G has been revised multiple times in the past, with the most recent update occurring in 2014.

4. Why is it important to have an accepted value of G with longitude?

Having an accepted value of G with longitude is important because it allows scientists to accurately calculate and predict the gravitational force between objects, which is crucial in understanding various phenomena in the universe. It also serves as a fundamental constant in many physics equations and theories.

5. Are there any factors that can affect the accepted value of G with longitude?

Yes, there are various factors that can affect the accepted value of G with longitude, such as the mass and distance of the objects involved, the accuracy of the measuring instruments, and the presence of other forces that may interfere with the gravitational force. Additionally, the accepted value may also vary slightly depending on the location and altitude of the measurement.

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