Does Mechanical Energy of a Planet Change in an Elliptical Orbit?

AI Thread Summary
The mechanical energy (ME) of a planet in an elliptical orbit remains constant throughout its motion, as the total mechanical energy of the system is conserved. While the planet's kinetic and potential energy fluctuate during the orbit, the sum of these energies, which constitutes the mechanical energy, does not change. The precise definition of ME in a two-body system includes both kinetic energy due to the planet's velocity and gravitational potential energy relative to the star. Thus, even though the individual components of ME vary, the overall mechanical energy remains constant. Understanding this principle is essential for analyzing planetary motion in elliptical orbits.
mancity
Messages
26
Reaction score
2
Homework Statement
Given an elliptical planetary orbit of a planet and a star, do:
(a) the mechanical energy of the planet change during the orbit? If so, describe the motion.
(b) the mechanical energy of the planet-star system change during the orbit? If so, describe the motion.
Relevant Equations
ME=KE+PE
Obviously the mechanical energy of the total system remains the same.

But I'm having a hard time determining of the ME of the planet is constant or if it is changing.
 
Physics news on Phys.org
mancity said:
Homework Statement: Given an elliptical planetary orbit of a planet and a star, do:
(a) the mechanical energy of the planet change during the orbit? If so, describe the motion.

But I'm having a hard time determining of the ME of the planet is constant or if it is changing.
What's the precise definition of the ME of a planet that is part of a two-body system?
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top