Gravitational Definition and 1000 Threads

Homework Statement There is a point between the Earth and the moon where the total gravitational field is zero. Given that the mass of Earth is 6.0*10^24 kg, the mass of the moon is 7.3*10^22 kg and the radius of the Moon's orbit is 3.8*10^8 m, calculate the distance of this point from the...

Homework Statement Lets say I have two objects, with the same mass, m, and charge (+q), with a distance r between them. They repel each other due to electrical force, but they are attracted due to gravitational force. My questions is: What should be their mass m such that they feel no net...

Homework Statement I'm trying to solve problem a problem of complete energy of doubled pendulum (2 mathematical pendulums connected by a string). For a kinetic energy I would get (1/2) J(w_1)ˆ2 + (1/2) J(w_2)ˆ2 and for a potential energy of a spring (1/2) k (ϕ_1-ϕ_1) What about gravitational...

Hello, Special arrangements of charged material can be used to accelerate charged objects or particles, e.g. a cathode ray tube. I am just wondering if it would be somehow possible, in principle if not in practice, to accelerate objects with gravitational force using special arrangements of...

Is there any relationship between the Speed of gravitational waves and the Universe's "local" expansion rate? Speed of gravitational waves is supposed to be equal to the speed of light. Gravitational waves don't travel faster than light. But we can observe far galaxies moving away from us with...

Find the Force of Gravitation between two Uniform Rods of Mass M and Length L. I heard my prof say that we have to do double integration to solve this. Please explain the above step and step with Diagram

Hello! I am implementing the three body restricted problem numerically (2 of them are massive and the 3rd one is not affecting them, so it is just moving in the potential created by them). I implemented it and if I put the 3rd one close to one of the big ones it moves in circles around it, while...

Homework Statement I need help getting started with this problem At what altitude above the surface of the Moon must a lunar module orbit in order to complete each orbit in 1 h 49 min 39 s? Homework Equations g= Gm/r^2 ? The Attempt at a Solution Not quite sure how to start or anything , any...

Can we experimentally measure the very weak gravitational force between two objects just like we can detect magnetic field lines by a deflecting compass.

Hi. I would like to know if it is possible to "reverse engineer" the formula below to find (G) if Ve, M and r are all known values. Ve = sqrt{2GM/r} Ve would be escape velocity, G would be gravitational constant, M would be mass of planet and r would be radius of planet. I hope I am...

I am confused on where the gravitational potential energy is in this solution. Thank you

Homework Statement I have a 100 lb mass that is attached to a disk which is rotating freely about an axle. How do I calculate the gravitational energy contributed buy this 100 pound mass as it rotates from the 12 position to the six position Homework Equations No clue maybe. M x g x h? The...

Suppose a gravitational wave propagating through space encounters a strong magnetic field (for example the wave might pass through a magnetar with a B field strength of 10^{11} Tesla). Would there be any observable perturbation in the magnetic field itself? In other words would the gravitational...

My understanding is that gravitational waves have not been detected from the proposed inflationary epoch of the big bang, only from the merger of two super massive objects. Is that correct? Are GWs predicted from the big bang in models where there is no inflationary epoch? If GWs are detected...

Several questioners ask if the Hubble red shifts could be gravitational red shifts rather than space-expansion red shifts. I understand why the answer has generally been "no". However, can I try this variation of the question... Red-shifting is apparent mostly for distant galaxies, which are...

Hello. And i have a dumb question about light. When the diffraction is studied, we look at where the light is coming. But not where the light comes from. When the gravitational deviation is studied, we look at where the light comes from, but not where the light comes. What do you think...

I'm puzzled that the stretching of space by a gravitational wave stretches the LIGO arm but not the light within it. Because we are told that the red shift of a distant galaxy is caused by light being stretched by the expansion of space (the universe).

The gravitational potential energy of two massic points ##P_1## and ##P_2## with respective masses ##m_1## and ##m_2## is given by $$U = -G \frac{m_1 m_2}{|| P_2 - P_1 ||}$$ Now I was wondering how this formula could be applied to continuous matter. Let us imagine a very simple case where we...

Homework Statement At what rate is the gravitational force doing work on a 2.0 kg projectile at an instant when the velocity of the projectile is 4.0 m/s directed 30 degrees above the horizontal. the answer is -39 W but i need help on why! Homework Equations P = W/T Power = Work*V...

The gravitational field of some massive body appears one way to a nearby stationary particle. But does the field appear to be distorted to a particle traveling at relativistic speeds?

Why are clocks not used to measure gravity waves? Spacetime wriggle and time must also vary. It is possible to measure time very accurately and with a high resolution. Så why not use clocks to detect gravity waves?

does any object with mass that moves create a gravity wave? So if I wave my hand it is in fact creating gravity waves, just very small ones

Sorry if something is wrong... this is my first ever post 1. Homework Statement The Question: In one dimension, the magnitude of the gravitational force of attraction between a particle of mass M1, and one of mass M2 is given by: F(r)=GM1M2/r^2 Where G is a constant and x is the distance...

I'm aware that the LIGO system uses interferometry but I'm confused how it works in this case. Do they test both beams of light? Or do they use one beam to test the wavelength of the other and see the difference? Also it is sensitive up to 10 e-18 meters, is that for the change in wavelength or...

I am sure this question includes multiple mistakes, so please bear with me. Gravity is force that is capable of doing work (moving objects over a distance). So under some circumstances, force of gravity is a form of energy or potential energy. How much gravitational energy/potential energy...

does mass affect the motion of the vertical upward, vertical motion down, free fall motion, and parabolic motion?

Suppose at the instant a gravitational wave passes through an interferometer, one of the interferometer's arm get stretched by 1%. Would the wavelength of the photon traveling in the arm also get stretched by 1%? If so, then would the frequency of the photon remain the same and hence increasing...

I am thoroughly confused regarding the modeling and graphic depictions of gravitational wave propagation. These waves must propagate in three dimensions, not in the planar rubber sheet example that is often shown or the ripples on a pond example. Even the recently publicized example of the...

Homework Statement 4 10kg objects are located at the corners of a rectangle sides 2 meters and 1 meter. Calculate the magnitude of gravitational force on 1 due to the other 3. (Same sort of idea) 3 1kg objects are located at the corners of an equilateral triangle of side length 1 meter...

Homework Statement I have a problem with question (b), in what follows there's a quote of the problem and its solution. (again from Bergersen's and Plischke's textbook). Homework EquationsThe Attempt at a Solution [/B] My problem is with the last expression in (d) I get 54 instead of 36. To...

Is there a theoretical limit to the size of neutron stars? It seems likely neutron stars are not simply electrons orbiting a proton so what is their life cycle? Can they just evaporate slowly by neutron decay?

Dear All Can anyone explain for me what is meant by gravitational anomalies in gauge theory? What is the difference between it and gauge anomalies? Thank you

I have no idea where this belongs or if it will be deleted but would Alcubierre drive cause detectable gravitational waves? And since I'm heading out on this limb would the direction of propulsion be indiscernible? As per the Wikipedia description it follows from a solution to the same general...

do we know for a fact that the gravitational constant has always been the same since the dawn of the universe? I feel like gravitational forces should slowly be decreasing as the universe ages (meaning that assuming mass of Earth doesn't change, we should weigh a bit less in a billion years)...

Homework Statement I have a particle of mass m. The particle is moving in direction of axis z because of the gravitational force of a homogeneous circular disk of mass M and radius a. There is a formula for gravitational force of the disk on the picture. Task: 1) Find the formula of...

Hello! I was wondering if the electric and gravitational fields are the same for a moving and a stationary object. The electric field (assume it is created by a stationary charge) is ##E = \frac{q}{\epsilon_0 4 \pi r^2}##, for a stationary observer, but it is higher for a moving one, as the r is...

Hi all I read a question on this subject from some time ago but was not satisfied with the clarity of the answer and in the light of recent experimental results I wish to clarify my understanding of this ancient scientific question. What is the cause of Inertia? So is inertia simply the total...

As the star runs out of nuclear fuel, some of its mass flows into its core. Eventually, the core is so heavy that it cannot withstand its own gravitational force.The core collapses, which results in the giant explosion of a supernova. Source...

In flat Minkowski spacetime, everything that travels at c, relative to some observer, it travels the same speed relative to any observer. If we refer to gravitons as bosons through this flat spacetime, it is clear they can be defined as traveling at c. And you can even some classical...

Since gravitational waves have energy, they can curve space all by themselves. I wonder in what conditions, if any, two gravitational waves could orbit each other. Thanks.

I want to pursue the sciences but I got no green. So I joined the BreakthroughJuniorChallenge in the hopes of winning! I would appreciate it if someone as knowledgeable as the people on this forum could comment and share my video submission. This is the link: It's also fine if you guys just...

Dear all, to keep me busy on a Sunday I considered the "1-body radial movement in a (Newtonian) gravitational field problem". I was a bit surprised to find it quite hard finding decent explanations on it. My question is: does anyone have a reference of the explicit solution to the particle's...

Homework Statement I was going through a worked example in my textbook to gain a better understanding but after I had a go myself it is the opposite to what I have calculated. I have attached the worked example which asks you to calculate the gain in gravitational potential moving from a point...

That is to say, how does time behave in a region of space where multiple gravitational fields cancel out their accelerating effects? I understand that time "slows down" in a gravitational field, but does this depend on the actual presence of the field, or instead the actual net acceleration...

I have a question about the gravitational time dilation explained in Appendix B of the book "Cosmology" written by S. Weinberg. Why can the author say "In the negative gravitational potential at the surface of a star clocks therefore tick more slowly than in interstellar space, or in the much...

There is a video on YouTube where Sean Carroll says for Newton it was just an accident that inertial mass equals gravitational mass, but with the general theory of relativity it became obvious that it has to be so. How does one see that? My own attempt has been consisting of transforming...

Dear all, In a recent talk, I have heard that speed of gravitational waves is non-dispersive. How is it proved "observationally" in LIGO detections that all the frequencies travel with the same speed, so one can say the speed is non-dispersive?

I'd like to call attention to this paper: https://arxiv.org/ftp/physics/papers/0409/0409124.pdf I'm not trying to question the validity of GR in bending of light near a star (such as the sun), as this paper apparently does. But surely Newtonian refraction of light passing through the sun's upper...

Is it possible for a transition between two atomic states to proceed by emission of gravitational, rather than electromagnetic, radiation?

problem 3.8 Classical mechanics R.Douglas Gregory A narrow Hole is drilled through the centre of a uniform sphere of mass M and radius a . Find the gravitational force exerted on a particle of mass m which is inside the hole at a distance r from the centreF = GMm/r2(i) interior to a uniform...