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Inverse-square law gravitational field ( free-fall time for two point objects on a radial path)

Description

Two objects in space orbiting each other in the absence of other forces are in free fall around each other. The motion of two objects moving radially towards each other with no angular momentum can be considered a special case of an elliptical orbit of eccentricity e = 1 (radial elliptic trajectory). This allows us to compute the free-fall time (as a function of separation) for two point objects on a radial path.

Related formulas

Variables

tyThe time after the start of the fall (s)
yThe distance between the centers of the bodies (m)
GNewtonian constant of gravitation
m1The mass of one of the objects (kg)
m2The mass of other object (kg)
y0The initial value of the distance between the centers of the bodies (m)