An object which experiences two gravitational force

AI Thread Summary
The discussion revolves around calculating the trajectory of a hypothetical Voyager 5 influenced by two gravitational forces from identical Earth-like bodies. The challenge lies in the changing forces due to the object's movement, complicating the calculations. Participants suggest using numerical methods, such as spreadsheets or programming, to simulate the motion step-by-step, adjusting for acceleration, velocity, and position iteratively. The conversation also touches on the complexities of the three-body problem, which lacks a straightforward analytical solution and requires calculus. Ultimately, the user plans to utilize Microsoft Excel for their calculations.
adjacent
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Homework Statement


attachment.php?attachmentid=68888&stc=1&d=1398073020.png

Let there be a Voyager 5 with two Earth's(I mean they have the same mass and density etc)
At start,Voyager 5 will be stationary.
I want to calculate the path of the Voyager and if possible,draw it on a graph.

Homework Equations


##F=\frac{GMm}{r^2}##


The Attempt at a Solution


I know I have to find the resultant force and accelerate the voyager in that direction.
My problem is that if I move it a little bit,the forces will change both direction and magnitude.Then I will again have to find the resultant force and accelerate it.This would be boring.
Is this really that difficult?Is there any other way?
I need your help here. :smile:
 

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This is known as Euler's three-body problem, and its analytical solution requires calculus. If I remember correctly, you are not there yet.

You could try solving this numerically, using a spreadsheet or some programming language, if you know one.
 
voko said:
This is known as Euler's three-body problem, and its analytical solution requires calculus. If I remember correctly, you are not there yet.

You could try solving this numerically, using a spreadsheet or some programming language, if you know one.
:cry:
I don't know any programming languages.How can I use a spreadsheet to solve this?

P.S can you recommend a calculus book that will teach it from scratch?
 
voko said:
This is known as Euler's three-body problem, and its analytical solution requires calculus. If I remember correctly, you are not there yet.
Even the two-body problem needs calculus to find a solution. The three-body problem has no "nice" solution for the general case.

@adjacent: The idea is to calculate the motion in small steps. For each step, calculate the acceleration, adjust the velocity a bit accordingly, adjust the position a bit accordingly. The quality of the trajectory depends on the step size and the order and formula of those adjustment steps, but to get an idea how it works that does not matter.
 
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In a spreadsheet, you would arrange rows of cells, where each row has two cells for position, two cells for velocity, two cells for acceleration, all at some instant of time. The acceleration in each row is computed using the force formula for the position in the row. The position in each row is computed from the position in the previous row plus the velocity in the previous row times the time step between rows. The velocity in each row is computed from the velocity in the previous row plus the acceleration in the previous row times the time step between rows. You need to set up just the first two rows in that way, then using the spreadsheet auto-complete feature (select cells and drag them down) to obtain more rows.

As for learning calculus from a book, it can be done, but is much harder than learning it from a teacher. I would not recommend doing that.
 
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mfb said:
Even the two-body problem needs calculus to find a solution. The three-body problem has no "nice" solution for the general case.

In this particular case, there is a (somewhat) nice solution.
 
Thanks everyone.I will try to use Microsoft Excel.
 
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