Energy
The specific orbital energy is negative, and
Thus the virial theorem applies even without taking a time-average:
- the kinetic energy of the system is equal to the absolute value of the total energy
- the potential energy of the system is equal to twice the total energy
The escape velocity from any distance is √2 times the speed in a circular orbit at that distance: the kinetic energy is twice as much, hence the total energy is zero.
Read more about this topic: Circular Orbit
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