What Is the Gravitational Force Between Two Rocks in Space?

AI Thread Summary
The gravitational force between two identical rocks, each with a mass of 2 kg and separated by 30 cm in space, can be calculated using the formula F = G (m1m2/r^2). The initial calculation yielded an incorrect force of 3.804 x 10^-8 N, which was later identified as a typo. The correct gravitational force is actually 2.96 x 10^-9 N. The discussion emphasizes the importance of accurate calculations and proper notation in physics problems. Accurate results are crucial for understanding gravitational interactions in space.
BrainMan
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Homework Statement


Two identical rocks of mass 2 kg drift through space far from any planet or star. If they pass one another at a separation of 30 cm, what is the magnitude of the gravitational force of one rock on the other at this instant.


Homework Equations


F = G (m1m2/r2)



The Attempt at a Solution


(4/.32)(6.673 x 10-11) = F
(4/.09)(6.673 x 10-11 = F
44.444444444444(6.673 x 10-11 = F
F = 3.804 x 10-8 N
the actual answer is F = 2.96 x 103 N
 
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BrainMan said:

Homework Statement


Two identical rocks of mass 2 kg drift through space far from any planet or star. If they pass one another at a separation of 30 cm, what is the magnitude of the gravitational force of one rock on the other at this instant.


Homework Equations


F = G (m1m2/r2)



The Attempt at a Solution


(4/.32)(6.673 x 10-11) = F
(4/.09)(6.673 x 10-11 = F
44.444444444444(6.673 x 10-11 = F
F = 3.804 x 10-8 N
the actual answer is F = 2.96 x 103 N

The "actual answer" is not correct, but it is the order of magnitude that is wrong not the mantissa of the number. Perhaps you misquoted the power of ten?

Regarding your solution attempt, your formula is fine but your math is not right. Recheck your calculation.
 
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gneill said:
The "actual answer" is not correct, but it is the order of magnitude that is wrong not the mantissa of the number. Perhaps you misquoted the power of ten?

Regarding your solution attempt, your formula is fine but your math is not right. Recheck your calculation.
OK I see my mistake and the answer I put was a typo it is actually 2.96 x 10-9 N
 

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