How long for 2 particles to collide due to gravity?

Thread starter thecommexokid
Start date Jun 26, 2013
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Gravity Particles

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SUMMARY

The discussion focuses on calculating the time until two particles, with masses m1 and m2, collide under gravitational attraction when released from rest a distance D apart. The gravitational force is defined by F_G(t)=Gm_1m_2/r(t)^2, and the center of mass plays a crucial role in determining the collision time. Participants explored various approaches, including using energy conservation and differential equations, ultimately leading to a complex integral that requires advanced calculus techniques for resolution. A specific solution for D = 1m yields a collision time of approximately 96136 seconds when both masses are equal to 1kg.

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Understanding of Newton's law of gravitation and gravitational force equations.
Familiarity with concepts of center of mass and its calculation.
Knowledge of differential equations and their applications in physics.
Proficiency in integral calculus, particularly with separable and trigonometric integrals.

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Study gravitational interactions in multi-body systems using Newton's laws.
Learn advanced techniques for solving differential equations in physics contexts.
Explore energy conservation principles in gravitational systems.
Investigate numerical methods for solving integrals that arise in physics problems.

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Physics students, researchers in gravitational dynamics, and anyone interested in the mathematical modeling of particle interactions under gravity.

Jul 9, 2013

BruceW

Science Advisor

yeah... hopefully he will be back soon. I am curious about this 'original method'. I cannot guess how it would work from the short description you gave.

edit: I mean, that I can substitute r with u and dr with du. But then the integral it gives is not any nicer at first glance (maybe my brain works differently to whoever did the original method). But anyway, I can wait 'till the OP comes back.