Gravitational Definition and 1000 Threads

The Michelson-Morley Experiment (as depicted in the scishow YouTube video "The Greatest Failed Experiment Ever") which was used to test for the effects of 'Aether Wind' appears to be almost, if not completely, the same setup as the one used in a gravitational-wave observatory. Why is the success...

Hi, First: I'm pretty sure my question has been asked numerous times, so I'm absolutely happy with links to other threads. I've used search but it didn't come up with satisfying responses, probably mainly because I don't really know what search terms to use. So the question is: How can a...

Homework Statement Homework EquationsThe Attempt at a Solution Consider a very thin shell of width dr at a distance r from the center . The volume of this shell is ##4 \pi r^2 ## . Mass is ## m = 4 \pi r^2 \rho## . P is the pressure at distance r . Gravitational acceleration at distance r <...

Hello! Let's say our gravitational potential is (as usual for 2 body), $$a = -\frac{\mu}{r^3} \mathbf{r}$$. Then the gradient of this is G, $$\frac{\partial G}{\partial \mathbf{r}} = G = \frac{\mu}{r^3} [3 \hat{\mathbf{r}} \hat{\mathbf{r}}^\top - I] $$ Now if we take two time derivatives of...

Hello all. I'm trying to determine the mass of an object required to make it so that a traveler on a massive planet experiences 1 day but on earth, or some infinitely distance away from the planet, 1000 years passes by. I'm using the following equation: t0 = tf*root(1-(2GM/rc^2)) Found here...

Homework Statement Calculate the gravitational force between a point mass and a circular platform. Homework Equations G=m1*m2/r^2 The Attempt at a Solution http://i.imgur.com/dfZf9GK.jpg The actual solution is different. They integrated by the angle between a/r (alpha) but i do not...

As I understand a photon has zero rest mass (as far as we can tell) but it does have a passive gravitational mass in order for it to be able to respond to gravity. But I've been shown that passive gravitational mass should be equal to active gravitational mass, and if this is true and photons...

I read that in 2014 the gravitational constant was measured by atomic intereferometry. Now I read that they speculate that measurements of G are in correlation with 5,9 years cycle. But, when we can expect new measurements of G? Are they in preparation?

Homework Statement Hi everybody! Here is a new Lagrange problem I am trying to solve, and I would like to have your opinion about my solution so far! A barbell composed of two masses ##m_1## and ##m_2##, idealised as particles and separated by a distance ##a## from each other, moves in the...

Hey! I am about to start my Bachelor's thesis about General Relativity. My professor mentioned that my thesis might as well be related to Gravitational Waves. Do you think that it would be appropriate to work on Gravitational Waves for a Bachelor's thesis? Isn't it too advanced? Also, any idea...

Does the rest mass of an object increase when it acquires gravitational potential energy, and if so, is this the reason why Einstein believed that the inertia of a mass increases in the presence of other masses?

If things such as quantum entanglement and the expansion of space can travel faster than light, then why can't gravitational waves, which are vibrations of spacetime? I thought that only matter cannot move through space faster than light. Also, has it been 100 percent proven that gravity waves...

I hope I posted in the correct forum... So, to put it simply. Let's say we have a point mass "m" at rest on the event horizon of a black hole of mass "M" and we throw it directly toward the location of the black hole's singularity. The particles only does linear motion and does not orbit the...

Hi Guys,When we are finding the wasted energy when something is dropped a tower, we do this: mgH-0.5mv^2 My question is, does the velocity of the kinetic energy have to be vertical component, or can it be the impact velocity when it hits the ground? Thanks

Does methane gravitationally differentiate in air, or does fluid dynamics mess things up & make it mix in with the air?

(precursor: I have not formally studied GR) I have noticed that the gravitational constant found in classical gravitation is also used in GR. Why is this the case? Am I correct in thinking that the constant was determined by Cavendish and was for the classical theory of gravitation? So, my...

Suppose two masses are connected via a really strong spring, where one of the masses undergo an acceleration towards a relativistic speed, by say a rocket that leaves the scene soon after. When in isolation, (the two masses), they exhibit a sinusoidal oscillation to and fro. What is the...

Hello, I do not quite get this. Can anyone provide examples? " We may feel that it takes a force greater than the weight of the object being raised to lift it upwards, but it is not so. Provided the force is equal to the weight, the object will move upwards at a steady speed. "

If a planet has gravity that is 3,000 m/s^2 instead of 9.8 m/s^2, would time passage be significantly different, or what would one second on Earth be compared to one second on that planet?

During gravitational collapse, gravitational potential energy of the gas is converted to its internal kinetic energy so the internal energy of the clous of gas is said to be increased But isn't gravitational potential energy included in the internal energy? Shouldn't the internal energy remains...

Homework Statement Consider the equations for electric potential energy: and gravitational potential energy: GPE=m*g*h In the case of GPE, the potential energy increases as the distance between the two objects increases. This makes sense (to me), as the greater distance between the Earth...

Homework Statement I am having some trouble with gravitational force and fields and would like some confirmation if I am on the right track and approaching the questions correctly. I have attached a couple of problems that I have worked through below. Homework EquationsThe Attempt at a...

Homework Statement Suppose that a 15 M(solar masses) star finally runs out of nuclear fuel in its core and undergoes a Type II supernova explosion. You are going to analyse the energy budget, calculating all the quantities in Joules. a) Estimate the amount of gravitational energy that would be...

This is something I've been curious for some time. I've heard that there is a relation between gravitational waves and black holes. Moreover, this year the quite important paper "Observation of Gravitational Waves from a Binary Black Hole Merger" was published. Now, I'm starting to study...

Currently I'm in the last year of the Physics course and I'm interested in working on some undergraduate research project. At first I was suggested to work with statistical physics, but I believe I would prefer working with General Relativity. From the point of view of background I do have a...

Homework Statement Consider a homogeneous thin ring of mass 2.5 x 1022 kg and outer radius 3.9 x 108 m (the figure). (a) What gravitational attraction does it exert on a particle of mass 69 kg located on the ring's central axis a distance 3.7 x 108 m from the ring center? (b) Suppose that...

I know that the speed/acceleration of a star can be measured using redshift/blueshift caused by the motion of stars, but I just learned that gravitation also causes redshift and blueshift. Would this not cause some uncertainty into the determining how fast a star is moving away from us? If so...

Hello, I am wondering how is the magnitude of the time dilation in a gravity field related to the time dilation we know from special relativity. How does the dilation caused by just being in the field compare to the dilation you'd have from your velocity if you fell into the gravity field from...

To me, it seems that with our current technology it would be difficult to observe the speed of gravitational waves. Can anyone correct me if I am wrong?

Suppose the mass of planet is" M" and there is body in its surface whose mass is "m" and the field strength is "g" . If the body is thrown 1800 m then Gravitational Potential energy = mg(1800). My question is why can't we use formula GPE= GMm/x ? This is also the formula for gpe but why...

hi, i'm totally confused right now. I'm playing around with a simple orbital model of the sun and the earth. since my rigid body solver doesn't like the huge masses of those bodies, i just normalized the masses to those of the sun. so i have m_sun = 1 and m_earth=3.0044e-6 as dimensionless...

Homework Statement Homework Equations ΔPE = G × M₁ × M₂ (1/Ri - 1/Rf) where G = gravitational constant M₁ = mass of one object M₂ = mass of the other object Ri = initial distance Rf = final distance ΔPE = -ΔKE The Attempt at a Solution My solution is v = 2√(GM/d). I am making sure it is...

hello, I was reading a recent article about gravitational waves and I had a few questions... I actually have a lot of questions, but I digress. Let me first start with what I think I know to be right, and then move on to the questions about the subject. -Time and space are connected. This...

I was looking at the wikipedia page for the gravitational binding energy of a sphere, but let's say that there was a toroidal planet. What would its gravitational binding energy be? I have attempted the solution similar to what they did on wikipedia and obtained: U = -4 G \pi^5 R^2 r^4 \rho^2...

Homework Statement There are three particles; 1) 26kg at 12i-hat 2)13kg at -5j-hat 3)13 kg at 5j-hat A) What is the gravitational force on the 26kg mass due to the 13kg mass at -5j-hat Homework Equations F= GMm/r^2 The Attempt at a Solution A) IN COMPONENTS; Y Component...

The Einstein gravitational constant (Κ) is usually written as; Κ = 8πG/c4 Can this constant be represented as wave-particle ratios of force? One ratio is a thermal ratio, it includes Plank temperature and Hawking temperature. The other ratio is a particle ratio including Plank mass. Can...

Hi all, this is my first post so before my question I want to show my appreciation to this community for offering a great framework to talk physics between experts and others who chose different life career paths, such as me. I have always loved physics but the math... not that much. English is...

Homework Statement "How much energy is released when a sphere of constant density (p) with mass (M) and radius (R) is put together gravitationally? What you should do is to think of the energy released when a shell is brought in from infinite distance (where potential energy of zero) to the...

Homework Statement A 400-N child is in a swing that is attached to a pair of ropes 2.00 m long. Find the gravitational potential energy of the child-Earth system relative to the child’s lowest position when (b) the ropes make a 30.0° angle with the vertical Homework Equations Ug=mgy The...

Hi all, I am very confused about the graphs of gravitational potential and gravitational field strength... I know that both gravitational field (g) and electric field strength (E) are negative gradient of their corresponding potential (Vg and Ve). If so, shouldn't g and Vg graph look very much...

Hi all. Our lecturer gave us an exercise the other day regarding an elastic gravitational collision between a planet and a satellite where the satellite slingshots using the gravitational field of the planet. The question asks to show that ##v_{f} - v_{i} = 2v_{0}## where ##v_{f}## is the final...

In 1916 Einstein has published the first paper of gravitational wave bu linearize approximation but It contain an error of his calculation then In 1918 he published a new paper of gravitational wave that has a correction of the his last error and conclude that there are the Gravitational wave...

How will be the gravitational effect of an object which is accelerated until reaching 1.5 times of its inertial mass? (According to space and satellites of this object)

Consider a system contained in a very tall adiabatically isolating vessel with rigid walls initially containing a thermally heterogeneous distribution of material, left for a long time under the influence of a steady gravitational field, along its tall dimension, due to an outside body such as...

Hi, so Newton said that gravity was like or equivalent to a force? When I learned about SR we were talking about the passing of time as defined by a photon bouncing between two parallel mirrors. So when we're sitting our two parallel mirrors in a gravitational field, even though I suppose...

Homework Statement A 60 kg skier is beginning her descent down a 26 degree slope. The frictional force between the skis and the snow is 4 N a) What is the gravitational force the skier exerts on the slope? b) What is the normal force the slope exerts back on the skier? Homework EquationsThe...

Many have claimed that if dark energy was not so small then the universe would fly apart and we wouldn't be here. However what if you increased the value of lambda and at the same increased the value of the gravitational constant ( or perhaps the amount of matter or dark matter in the universe)...

Homework Statement A particle of mass 52[kg] is at 5.0[m]ˆi a particle of mass 13[kg] is at 12[m]j, and a particle of mass 13[kg] is at −12[m]jˆ. What is the gravitational force on the 52[kg] mass due to the mass at 12[m]jˆ? answer: −1.0 × 10−10[N]ˆı + 2.5 × 10−10[N]jˆHomework Equations...

Homework Statement Two neutron stars are separated by a distance of 4.80 E 10 m. They each have a mass of 3.60 E 30 kg and a radius of 1.30 E 5 m. If they are initially at rest... How fast is each star moving when their separation has decreased to half its initial value? How fast is each star...

This pertains to a homework question but I get the concept of PE or U = -GmM/a for an elliptical orbit. I also understand the derivation of the total energy of an object in an elliptical orbit as E = -GmM/2a. However, I have a homework question that asks for the ratio of an object's kinetic...