Universal and Gravitational Force

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SUMMARY

The discussion centers on the principles of gravitational forces and energy conservation in satellite orbits. It confirms that a satellite's total energy remains constant in an elliptical orbit, regardless of its position at Perigee or Apogee, assuming no friction. Additionally, it establishes that a satellite in a higher orbit (160 km) possesses greater total energy than one in a lower orbit (144 km) due to the weaker gravitational pull at higher altitudes. The total energy is calculated using kinetic energy (KE) and potential energy (PE) formulas.

PREREQUISITES
  • Understanding of gravitational forces and potential energy (PE = -GMm/r)
  • Familiarity with kinetic energy concepts (KE = 0.5mv²)
  • Knowledge of Newton's 2nd law for centripetal motion
  • Basic principles of orbital mechanics and satellite motion
NEXT STEPS
  • Calculate total energy for satellites in various orbits using KE and PE formulas
  • Explore the effects of orbital eccentricity on energy conservation
  • Study the implications of gravitational forces on satellite stability
  • Investigate the differences between elliptical and circular orbits in terms of energy
USEFUL FOR

Aerospace engineers, physics students, and anyone interested in satellite dynamics and gravitational physics will benefit from this discussion.

Neerolyte
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i have a couple questions to ask

1: When a satellite is in eclipsical orbit, the total energy should stay the same wether it is at Perigee or Apogee, neglicting friction, correct?

2: Which is larger - The total energy of the 2.00kg satellite in its 160km orbit or the total energy is its 144km orbit. Why the two answers are different?
 
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1: Pretty much, It depends on how eliptical the orbit is.
2: Well, of course the 160 km orbit, because Earth's pull is weaker.
 
Neerolyte said:
1: When a satellite is in eclipsical orbit, the total energy should stay the same wether it is at Perigee or Apogee, neglicting friction, correct?
That is correct. Total energy (KE + PE) is constant.

2: Which is larger - The total energy of the 2.00kg satellite in its 160km orbit or the total energy is its 144km orbit. Why the two answers are different?
The satellite in higher orbit has greater energy. To understand why, figure it out! Assume a circular orbit: use Newton's 2nd law for centripetal motion to find the speed and thus the KE. The PE = [itex]-GMm/r[/itex]. Now find the total energy for both orbits and compare.
 

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