Is it possible to use Newton's Law of Gravity AND Einstein's Theory of Gravity?

In summary, the conversation discusses how to use Einstein's theory of gravity to calculate the gravitational force of attraction between two point masses, and the difference between using Newton's gravity and Einstein's gravity in this calculation. It is mentioned that Einstein's equations do not calculate force but describe the shape of space-time, and that calculating the curvature felt by each object would be necessary. An example of a high-energy limit is also mentioned, along with a recommended book for further reading.
  • #1
studentxlol
40
0
to answer this question:

Q) A mass of 100kg is 50m away from a mass of 250kg (from centre of masses). Calculate the gravitational force of attraction between both point masses.

Could I use Einstein's theory of gravity to answer this question using the information given. If so, how would I go about doing it?
 
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  • #2
Since Newton's gravity is just a low-energy limit of Einstein gravity, you technically are using Einstein gravity when you compute [itex]F = {{GmM}\over{r^2}}[/itex] :D
 
  • #3
Pengwuino said:
Since Newton's gravity is just a low-energy limit of Einstein gravity, you technically are using Einstein gravity when you compute [itex]F = {{GmM}\over{r^2}}[/itex] :D

Ok. Give me an example of a high-energy limit and what extra information I need to calculate using Einstein's formula.
 
  • #4
studentxlol said:
to answer this question:

Q) A mass of 100kg is 50m away from a mass of 250kg (from centre of masses). Calculate the gravitational force of attraction between both point masses.

Could I use Einstein's theory of gravity to answer this question using the information given. If so, how would I go about doing it?
Einstein's equations don't calculate force. They describe the shape of space-time. Objects move along geodesics of the space-time. No force.
 
  • #5
So you would actually have to calculate the curvature felt by each object, which would be a kind of sum of the distortions from each mass?
 
  • #6
khemist said:
So you would actually have to calculate the curvature felt by each object, which would be a kind of sum of the distortions from each mass?
Yes. Probably the easiest calculation is the bending of light as it grazes the sun. There is an excellent book about this and very easy to read. "The Einstein theory of Relativity" by Lieber and Lieber.
 

1. Can Newton's Law of Gravity and Einstein's Theory of Gravity be used together?

Yes, both theories can be used together as they describe different aspects of gravity. Newton's Law of Gravity is applicable to everyday situations and objects with relatively low masses, while Einstein's Theory of Gravity is necessary for objects with very high masses or in extreme conditions.

2. How do these two theories differ?

Newton's Law of Gravity is based on the concept of gravitational force between two objects, while Einstein's Theory of Gravity, also known as General Relativity, explains gravity as the curvature of spacetime caused by the presence of mass and energy.

3. Which theory is more accurate?

Einstein's Theory of Gravity is considered to be more accurate as it has been proven to accurately predict the behavior of gravity in extreme conditions, such as near black holes, while Newton's Law of Gravity is only an approximation.

4. Can both theories be applied to all situations?

No, both theories have their own limitations. Newton's Law of Gravity is not applicable in situations involving very strong gravitational fields or very high speeds, while Einstein's Theory of Gravity does not work at the quantum level.

5. Can these theories ever be unified?

There have been attempts to unify both theories, but a complete and universally accepted theory of gravity has not been achieved yet. Some physicists believe that quantum mechanics and general relativity will eventually be unified in a single theory.

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