Gravitational field Definition and 366 Threads

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?

Homework Statement I have derived the expression for the velocity of the satellite v= root of GM/r however I'm struggling to derive an expression for the centripetal acceleration of a satellite orbiting Earth. Homework EquationsThe Attempt at a Solution I'm not entirely sure which equations to...

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

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...

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...

Can someone please tell me how the energy field created by warped space (gravity) and centred at the Earth's core dissipates? Is it the pressure/compression of this force/energy that makes the core so volatile? Whilst time slows at altitude, do we become lighter, as we are further away from...

Is anyone aware of a concise review of the experimental evidence of the nature of the gravitational field due to an entity in spatial superposition? Is it known (or generally presumed) that photons exert gravitational attraction through the stress-energy tensor at all points in space related to...

Homework Statement A uniform solid sphere of mass M and radius R is fixed at a distance h above a thin infinite sheet of mass density σ. Obtain the magnitude of the force between the sphere and the sheet. Homework EquationsThe Attempt at a Solution I've found the gravitational field from the...

I just read Carlo Rovelli new book "Reality is Not What It Seems: The Journey to Quantum Gravity" in one sitting and quoting the relevant passage: "The world is not made up of space + particles + electromagnetic field + gravitational field. The world is made up of particles + fields, and...

I know the formula for calculating field strength is g= GM/r2 , however if I'm trying to show the proportionality relationship between just g and m, would g ∝ m be correct, since a larger mass equals a stronger force of gravity and vice versa?

I have a few conceptual issues following a standard thought experiment to argue why light bends in a gravitational field and I'm hoping I can clear them up here. Consider an observer in a lift in free-fall in a uniform gravitational field and an observer at rest in the uniform gravitational...

Homework Statement I know that in general it is when the gravitational field is not constant, so that part is fine. To find the gravitational force between a sphere with mass M and a radius R and a thin rod of length L and mass m which has one end a distance x away from the center of the...

1. Homework Statement Homework Equations g = (Gm)/r2 The Attempt at a Solution I tried doing (Gm1)/a2 = (Gm2)/(r-a)2 where a is equal to the distance from the position we're trying to find to the center of the most massive object but end up getting a quadratic in the denominator on the right...

Hello, I would like to better understand the geometric evolution of a gravitational field of a simple point mass as the velocity difference between two different inertial frames approaches the speed of light. I would also then like to extend into more complex scenarios such as charged...

Homework Statement Consider a particle in a gravitational field that is also subject to a resisting force proportional to the velocity squared ( Fdrag = + or - cv2). a) Find the terminal velocity, vT, for the object as it falls. b) Show that for an object dropped from rest that the velocity...

I have read that: In 1915 Einstein presents to the Prussian Academy of Sciences the General Theory of Relativity; it includes a set of Gravitational Field Equations; at this time he does not present any solution to the equations. In 1917 he considers a greatly simplified case; presents a...

Sci Am August 2016 discusses a supervoid detected in the direction of the CMB cold spot. The analysis assumes the gravitational potential is less in the center of the void than near its edges (thus near its surrounding galaxies). On the other hand the gravitational field inside a spherical...

Book: Landau Lifshitz, The Classical Theorey of Fields, chapter 11, section 95. I have gone through the derivation of Einstein field equations but not without holes to fill and fix in my understanding. Let's start with the action for the grtavitational field ##S_g## which after some explanation...

Homework Statement What is the gravitational field strength at a point 6.38x106 m above the Earth's surface? Homework Equations The Attempt at a Solution Ok so I plug in all the known variables. G= 6.67x10-11. M= 5.98x1024. r= 6.38x106 and so I multiply that by 2 because the given point is...

Let's say there's a massive and uniform sphere of radius, r, and there's a box in its gravitational field and the sphere is so massive that the box is accelerated to a velocity near the speed of light; could the classical coordinate system still be used or is the Schwarzschild coordinate system...

As most of know that magnetic field arises due to change in electric field flux over a surface. In the same way, is there any kind of field arising due to gravitational field flux about a surface ? And if yes then does gravitational field and that field cause each other (in the same way electric...

In what scenarios would you use the equation g= F/m instead of g=GM/r2 (or vice versa), for calculating gravitational field strength? Update: is g=F/m used to find the force acting on a mass in a gravitational field (of strength g), whereas g=GM/r2 used to calculate the gravitational field...

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...

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...

Are spacetime and the gravitational quantum field (still hypothetical) separate entities? Would the gravitational field be more fundamental, one of the various entities from which spacetime as a whole is composed? Gravitons, which are believed to transmit the force of gravity, would surely be...

To note this is not for any piece of homework. Anyway, what possible masses and a distance between them are required for there to be a gravitational field strength of 1 Newtons per kilograms, when these figures are put into Newton's equation of F= G (m1 * m2 / r sqaured) Many thanks!

Please see the attached file if I have calculated the gravitational field g at the centre of a hemisphere correctly.

Question: There is a large parallel beam of incoming particles with mass m and uniform velocity v0 (v0≪c) in the presence of a gravitational field of a (spherical) planet with mass M and radius R. (without GR) The question is what fraction of the particles will eventually arrive at the planet...

Hello PF members, Source of the gravitational field in the Einstein field equations is energy–momentum tensor and the curvature of space-time is directly related to the energy and momentum of whatever matter and radiation are present. Suppose a electron at rest . 1- Can this electron be...

I'm trying to write a class for the gravitational field of any planet (I tested it with values for Earth though), and it gives completely the wrong answer! I suspect this is either a mathematical error, or an issue with my declarations of stuff as public, private, static etc. Compiles, just...

Hey guys, take a look at this question if you may Suppose the moon, instead of a sphere, is a disc orbitating the Earth ( the moon's total mass is equal to the disc's total mass), the intern radius of the disc is equal to half the distnce between moon and Earth's center of mass and the external...

Hi guys! What would happen to objects on the Earth's surface if it SLOWLY stopped spinning and Earth's gravitational field was kept as always. Thx

Dear friends! If there are two particles of unequal masses in a system on which there are no external forces.When let free they collide under the influence of gravitation. Should they always collide at CM. If the system were under an external force of uniform gravitational field will the...

bcrowell submitted a new PF Insights post How Fast Do Changes in the Gravitational Field Propagate? Continue reading the Original PF Insights Post.

The acceleration of free fall at the equator is not equal to the acceleration of free fall at the poles.explain?

Hello everyone! I have a question concerning the proof of Poisson's equation for a gravitational field. My question is how can i prove that Gauss's Law is independent of the choice of the closed surface surrounding the point mass? Thanks in advance

In weak field regime i know that it is possible to quantize the gravitational field obtaining a quantum theory of free particles, called gravitons, which is very similar to the one for the electtromagnetic field. Do you know some book in wiich i can study this theory? In anycase what is the...

Homework Statement "Complete the diagram to display gravitational field lines between two objects of equal mass." Homework Equations N/A as question is descriptive.The Attempt at a Solution Okay, I know it's a bit of a mess but what I'm trying to show here is that the fields are radial and...

This is an example at the beginning of the section on the Fundamental Theorem for Line Integrals. 1. Homework Statement Find the work done by the gravitational field \vec{F}(\vec{x}) = -\frac{mMG}{|\vec{x}|^3}\vec{x} in moving a particle from the point (3,4,12) to (2,2,0) along a piece wise...

1. Calculate the gravitational field strength at 500km above Mars' surface. Mass of Mars: 6.39 x 1023 kg Radius of Mars: 3.39 x 103 km Constant G: 6.67 x 10-11 2. I used the equation g = GM / r23. To begin with I added the 500km height above ground to the radius, giving 3.89 x 103 km. I then...

Homework Statement Earth actually has an electric field of 1.0 x 10^2 N/C at its surface pointing toward the center. (b) Compare Earth's electric field and gravitational field in terms of i) direction ii) shape iii) how it changes as height increases. c) What is the largest mass that can be...

Suppose I have a cylinder of gas and at time t=0 I can turn on a strong vertical gravitational force. Let the force change quickly (but a time long compared the mean free path divided by the average gas particle velocity) to reach some constant maximum value F(z,t) = F_max. (This force can be...

Am I reading some more recent articles on quantum gravity correctly that seem to be implying that a coherent particle is not subject to gravity? If you have a coherent C70 buckyball molecule (see Zeilinger - Update: "Matter-wave interferometer for large molecules", Jan. 2002), the force of...

Homework Statement Homework EquationsThe Attempt at a Solution I can't understand what is ɛ in this problem, and why should we adopt it. Could you explain me please?

Can someone help me with this question, Calculate the force of gravity on a 70-kg astronaut 2.0 Earth radii from the centre of Earth.

If light was being produced in an intense gravity field, would the light be of higher or lower frequency/energy to a distant observer? I understand that the light escaping the gravitational field would be red shifted, but that is not what I'm asking. I'm asking about the relativistic effects on...

√Homework Statement Show that the gravitational field due to thin uniform circular plate of radius a at point distant R from center and on the axis passing through the center and perpendicular to the plane of the plate is given by E= -2πGρ[1-R/(a^2+R^2)^1/2] Homework Equations F= GMm/r^2...

Homework Statement a) A mass ##m##, initially at rest, is released from infinity, and is attracted towards a planet of mass ##M##, displacing towards it in a direction parallel to the gravitational field lines present between the masses. Assuming that the only force acting on ##m## is the...

A 20 kg mass is situated 4m above the Earth's surface Taking g as 10 m/s2. What are the gravitational field strength and gravitational force acting on the mass? Am I wrong when I say that because the height of the mass ( which is 4m) is too little comparing with the radius of the Earth so that...