Ratio between change in Energy(Gravitational Potential)

Click For Summary
SUMMARY

The discussion focuses on the ratio of change in gravitational potential energy between two objects, A and B, at a specific altitude (h) above Earth. Object A transitions from rest to altitude without entering orbit, while Object B ascends to the same altitude and then enters orbit. Key variables include the radius of Earth (Re), the universal gravitational constant (G), and the masses of Earth (M) and the objects (m). The user seeks clarification on the correct calculation of energy changes, specifically whether to use total orbital energy (-Ek) for Object B and how to simplify the energy equations accurately.

PREREQUISITES
  • Understanding of gravitational potential energy (Eg) and kinetic energy (Ek)
  • Familiarity with the universal gravitational constant (G)
  • Knowledge of basic calculus for energy simplification
  • Concept of total orbital energy in gravitational systems
NEXT STEPS
  • Study the principles of gravitational potential energy and its calculations
  • Learn about total orbital energy and its implications in orbital mechanics
  • Review calculus techniques for simplifying energy equations
  • Explore the relationship between altitude and gravitational forces on objects
USEFUL FOR

Students in physics, particularly those studying mechanics and gravitational forces, as well as educators seeking to clarify concepts related to energy changes in gravitational fields.

fahlim003
Messages
3
Reaction score
0
Ratio between change of Energy(Gravitational Potential)

I would like some assistance in understanding the ratio of change in energy between two objects.

In this case, if object A goes from rest to an altitude (h) above Earth but does not begin an orbit versus object B goes from rest to the same altitude and then proceeds to orbit the earth.

The variables are as follows:
Re=radius of earth
h=altitude
G=universal gravitational constant
M=mass of earth
m=mass of object(A=B, also known as A and B are the same)

I'll need to transcribe my findings, which until now when comparing to my professors simplication are slightly off, a little later.

I was told my error might occur in the initial change of energies for the respective objects, and this may very well be true. However, I did come across great challenges at first when trying to find a GCF for the variable laden energies.

What I've been using prior to simplication:
Object A = change in Eg = Eg2 - Eg1
Object B = change in total energy = Ek - Eg1

Eg as known is a negative value while Ek is positive.

Any help is appreciated and I understand little help may be offered since I've yet to put up the actual attempts, but when I have more time I'll transcribe my most recent effort into mspaint.
 
Last edited:
Physics news on Phys.org
A good turnout.
Ok, here's my most recent work.

http://img410.imageshack.us/img410/3044/ratioworkingqk8.png


Am I not correct in choosing the E2 and E1 for the object heading into orbit?
I choose Total Orbital Energy (-Ek) since that is energy required to orbit for object B. Although, wouldn't it be possible to put change of energy for the object heading to altitude h as simply Ek instead of -Ek-(Eg)? I would really like some input on this.


Also, it's been a long time since I did any Calculus and or math in general, which may explain why I have trouble with simplification.

Some ratios, albeit told as wrong by my professor include:

http://img296.imageshack.us/img296/3913/resultseh6.png

With the last in the line being the earliest example and least correct.

As mentioned, the first two were said to be nearly correct, although it's been a few days since I spoke to her so I cannot say which is more correct.

Again, help is appreciated. Thank you.
 
Last edited by a moderator:

Similar threads

Replies
15
Views
2K
Replies
9
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
8
Views
2K