Gravitational energy Definition and 65 Threads

I made a note of the above quote a while ago and don't recall the source. I did not understand it then and in coming across it again I still don't...Can anyone explain?? Does this not completely ignore gravitational potential energy?

Homework Statement How much energy is required to launch a 200 kg satellite from the surface of the Earth into a circular orbit with radius 8.0 * 10^6 m? G=6.67*10^-11 Homework Equations Ep= -GMm/r The Attempt at a Solution I calculated the gravitational potential energy of...

An object orbits a star, both items comprise the system. I am looking for confirmation of a couple of concepts regarding orbits. As the object slows down, does the kinetic energy of the system decrease, and does the total energy of the system decrease? As the kinetic energy of the system...

Homework Statement How far would a 1.00 Kg ball have to fall freely to reach a speed of 100 Km/h ? Homework Equations \Delta E_g = \Delta E_k The Attempt at a Solution \Delta E_g = \Delta E_k i then expanded to: mgh' - mgh = \frac{1}{2}m(v')^2 - \frac{1}{2}mv^2 i...

Homework Statement A 70.0 kg skier rides a 2700 m long lift to the top of a mountain. The lift makes an angle of 14.3° with the horizontal. What is the change in the skier's gravitational potential energy? Homework Equations The Attempt at a Solution mg cos(?) * (h0 - hf)...

I know that gravitational energy is a delicate topic in GR. It is true that the localisation of gravitational energy is not possible in GR but it should at least be possible to determine correctly the sign of the gravitational energy. I found the following article in arxiv.org, nl...

I was just wondering if there were any applications of the equations U= GMm/r. Which basically means we are not to involve anything on Earth's surface. Thx

Q: An object at a height of 15 m above the ground is traveling at 25m/s. Find its a) kinetic energy b) gravitational energy If I find out how to do (a), I am sure I will figure out B. The problem is I don't know how to figure out (a) I know that Kinetic Energy = 1/2 mass (speed)^2...

Let's see if I can articulate this question the way that I'm thinking about it... Imagine you have a big star (like the sun)... and every so often a comet or meteor (or even several of them) whiz past. My understanding is that the star's gravity will influence the path of the comets and/or...

Calculate the gravitational self energy of the sun (without using numbers) Textbook says that this is the nergy needed to take every particle from the sun's surface to infinity there are an infinite number of particles on the sun ... would there be some sort of integral that relates the...

I remember that someone (maybe Hawking) said the total energy of cosmology is zero: the matter hold the positive energy and gravational field possesses the negative energy. But I can't understand it, why the gravational field's energy is negative? As far as I understood, from the view of gauge...

i have looked on the net for a formula that would give me an idea of how much gravitational energy verses other energies is given of when a massive body is destroyed, is there such a formula? or is it just that the mass of the body is converted into energy by E=M^2 and the gravitational...

is it not true that the total energy of the universe is zero? i heard somewhere that the gravitational attraction between objects is exactly canceled by the electromagnic force required to keep them apart at close ranges. this might only mean gravitational energy is zero. but gravity still is...

What is gravatational energy?

What is meant by the theory/fact that gravitational energy is negative? I would have thought that this would mean that gravity would cause objects to be repeled from each other