Gravitational Definition and 1000 Threads

Hi all, This is Newton's universal law of gravitation: F = GMm/r2, where r is the distance between the centre of the two bodies. Therefore, considering two objects in mutual gravitational acceleration, with only linear motion and acceleration, they shall be moving in closer and closer. Since...

Hi, the following two views appear inconsistent to me: In the infinite perfectly homogeneous universe: a) the net force of gravity is zero everywhere, so no energy is being exchanged and no particle is pulled in any direction whatsoever. b) the net force of gravity within a spherical...

Homework Statement Here is the pic: http://i.imgur.com/olnuDjL.jpgHomework Equations The Attempt at a Solution So intensity was pretty easy, it came up to be y=\frac{GM}{a^{2}}(1+\frac{1}{2\sqrt{2}},1+\frac{1}{2\sqrt{2}}) Check on if it's correct would be nice aswell. Now for potential I know...

Homework Statement So in this video: https://www.youtube.com/watch?v=rm3x2X0X_Sc&t=210 Why does g.out and g.in have values as shown on the video? I can not for life of my understand it. Homework Equations The Attempt at a Solution

I was studying the equations of free fall and of launch when I realize that those equations are spetial case of a object in motion through of a gravitational field. So exist some general equation that describe the motion (the trajetory*) of the object through of the field (using initial values...

Hi, I am a bit confused with the relationship between gravitational field strength and gravitational potential. As far as I know, gravitational field strength is defined as: g=\frac{F}{m}=\frac{GM}{R^{2}} and gravitational potential is defined as: V=\frac{-GM}{R} Now if I...

Homework Statement The space shuttle Endeavor is moving at a speed of 27870 Km / h. At takeoff, its mass is 2, 28 * 10 ^ 6 kg, however, its mass decreases as it uses its fuel: the engine burns liquid oxygen which has a density of 1141 kg / m^3, at a rate of 1340 liters per second. Calculate...

I'll be cautious in asking my my question because I'm out of familiar territory. But... Given the following: that dark matter interacts with baryonic matter (exclusively?) via gravity, that evidence for dark matter shows that it exists largely near baryonic matter, and we are (almost?)...

I know that normally we can ignore gravitational effects when considering interactions between subatomic particles. As I understand it the reason for this is that either they are interacting electromagnetically in which case the gravitational interaction is negligible or they are both fermions...

Hi people, please could someone enlighten me on gravitational time dilation. I have read online that some places, such as neutrons stars, warp time so much that time can pass 100 times slower than it does on Earth. I was just thinking about a human heart beating. If a healthy heart rate on Earth...

I'm reading: http://www.feynmanlectures.caltech.edu/I_13.html#Ch13-S4 1. In the link it says: ##2\pi\rho d\rho## is the area of the ring of the radius ##\rho## and width ##d\rho##, if ##d\rho \ll \rho##. Why is this true?? 2. A bit further down in the text it says: Since ##r^2 =...

1. Imagine two objects, A and B, answer the questions that follow based on the conditions given. A= 500g, at 2m, B=1.0kg, at 1m a. Which has a greater Gravitational Energy? Why b. If they are both dropped, which would have a greater velocity impact...

arXiv:1404.5682 arXiv:1404.5682 [pdf, ps, other] Assessing Pulsar Timing Array Sensitivity to Gravitational Wave Bursts with Memory D. R. Madison, J. M. Cordes, S. Chatterjee Comments: Submitted to ApJ Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for...

Homework Statement I have been trying solve this ask, but there is a problem. I don´t know how I can obtain an expression of infinity which is connected with angle. Picture is as Attach Files2. The attempt at a solution I think, I must use this equations AAB=m * ∫ * K dr = Δ Ek Is there...

Homework Statement Let there be a Voyager 5 with two Earth's(I mean they have the same mass and density etc) At start,Voyager 5 will be stationary. I want to calculate the path of the Voyager and if possible,draw it on a graph. Homework Equations ##F=\frac{GMm}{r^2}## The Attempt...

Can gravitational attraction (generated by a super-massive black hole, for instance) accelerate you faster than c?

We all can measure the mass of a body by any common instrument like Spring Balance. But if we go from one place to another place the gravitational force will change, like if we go from 1st floor to 10th floor or from coastal region to plateau region. The gravitational force depend on the...

Problem: Show that the combined spring energy and gravitational energy for a mass m hanging from a light spring of force constant k can be expressed as 1/2 ky2, where y is the distance above or below the equilibrium position. Figure shows a block connected to spring, where equilibrium is...

Quick question... Can the gravitational constant only be used for Earth or can it be used in questions regarding other planets?

Homework Statement If you lived on a planet with five times the mass of Earth and twice the radius, what would be the gravitational acceleration at the surface of your planet? Homework Equations GM/r^2 Mass of Earth = 6.00*10^24 kg Radius of Earth = 6.38*10^3 km The Attempt at a...

Homework Statement I'll provide a picture for a clearer view: http://i.imgur.com/wkXPcJn.jpg Suppose that the slender rod starts at rest at theta = 0. For convenience we chose the datum at theta = 0. Now I want to calculate the gravitational potential energy at a later instant when theta =...

Consider a spherical star made of N (very large number) particles interacting via gravity.Let the mass of ith particle be mi and position be xi Let ##I= \sum_{i=1}^{N}m_{i}r_{i}##, U be potential energy and K be kinetic energy 1)Show that the virial equation takes the form...

Hey guys, I feel like an idiot for asking this. However, I wanted to make sure that my head was screwed on straight before I asked my old astronomy professor permission to use some of his old lecture notes. Is gravitational redshift one of the causes of Hubble's Law? Is the Redshift of the...

In our dimensions, it is ~6.67384 × 10-11 m3 kg-1 s-2. I recall having read a Hawking article a long time ago in which the ideas of greater or smaller variations of this constant were toyed with, and what they would mean for their respective universes (with other constants unchanged from the...

This is not exactly a homework question. In a physics textbook, they derive an expression for gravitational redshift of a photon emitted by a star at a large distance from the source by taking photon as a mass traveling up, against a gravitational potential and hence expending its...

What is the gravitational binding energy in GR in the spherically symmetric case? I calculate ##E=mc^2(1-\frac{1}{\sqrt{1-\frac{r_s}{R}}})## where ##m## is the mass of the body, ##r_s## is the Schwarzschild radius, and ##R## is the area radius as in the Birkhoff theorem.

Greetings, Long time reader, first time poster, so try to go easy on me :redface: I'd love to get a sanity check on something my father discovered and I've been helping him refine. We're not professional physicists, so we've had to take to the Internet to discuss and collaborate. Before you...

Today, all of the scientific world (including /r/physics) buzzes about BICEP2's discovery of gravitational waves dating from Big Bang as an undispute confirmation of the general relativity. Now I wonder is it really GR? Can't it be explained by simple Newton's mechanics? I mean if you can...

Hi there guys. As the title implies I'm trying to draw a trajectory on the screen (yes, this is indeed about programing :P) involving multiple sources of gravity. Here is my dilemma: Since I'm working with an update loop there would be no problem to just simulate an object and having it...

So I created an account here just so I could ask this burning question. I keep looking online and through other resources but can't really find any details on this. Apologize if I didn't post on the right forum. So I know gravitational waves are still being studied and as far as I know any...

In nature, all forces have a limited value, i.e, their effect is reduced if many objects are influenced by that force. Example, the magnetic force experienced by a single iron nail (in a magnetic field) is greater than that of 2 iron nails in the same field. Consider gravity, gravity exerts...

Homework Statement Homework Equations torque = r*Fsin(x) The Attempt at a Solution I really need help on walking through this problem...didn't really teach it in class...I tried watching a video and you're supposed to sum the forces * some perpendicular distance to the pivot...

Homework Statement How far from a very small 110kg ball would a particle have to be placed so that the ball pulled on the particle just as hard as the Earth does? Homework Equations Fg= gMm/r^2 The Attempt at a Solution I used the equation and plugged in the numbers for the ball...

Homework Statement The gravitational attraction due to a nearby mountain range might be expected to cause a plumb bob to hang at an angle slightly different from the vertical. If a mountain range could be represented by an infinite half-cylinder of radius a and density ρ lying on a flat plane...

When Earth pulls a mass with gravitational force why does the energy of the earth-mass system decrease? Isn't work just transfer of energy meaning constant overall energy?

Gravitational Potential energy is the work done against the gravity to move a mass from one point to the other. So if a mass was falling down to the earth, how is the potential energy defined?

Why is gravitational potential energy defined at infinity? Like here on Earth there is Zero potential energy at the center of the Earth (if you could theoroeetically go there) so why not define it as 0 at zero distance from the force supplier instead of at infinity? I understand why the...

Null results so far for the elusive gravitational search, but were they expected to be found at this range? arXiv:1402.4974 (cross-list from gr-qc) [pdf, ps, other] Implementation of an F-statistic all-sky search for continuous gravitational waves in Virgo VSR1 data J. Aasi, B. P. Abbott, R...

Ok this one is purely theoretical and I'm going to just make some assumptions. 1. No Debris will block the way. 2. Its A vacuum 3.The structure won't collapse. Ok, first we drill a hole through one side the Earth and out the other. We then wrap the new whole in a superconducting coil of wire...

Hi everyone, I'm a college student enrolled in an astronomy course, and simply put, science and math in general are both quite possibly the two things I'm worst at! Anyways, I have a test coming up and our professor gave us a practice test, and after a lot of studying, I was able to figure out...

So, I asked myself the question, "why does the Earth's force of gravity effect us so dramatically on the surface of the earth, but seems nonexistent while just a couple hundred miles up?" I answered that question myself, after thinking more about it, because the idea of an orbit is that you...

Homework Statement The drawing (not to scale) shows one alignment of the sun, earth, and moon. The gravitational force vector F SM that the sun exerts on the moon is perpendicular to the force vector F EM that the Earth exerts on the moon. The masses are: mass of sun = 1.99 1030 kg, mass of...

Hello there, I was taught: a = {v^2 \over R}. I substitute v for the speed of the rotating Earth at the equator, and the radius, R = 6378m. And I get a = 0.03 \rm m/s^2. It looks like the equation a = {v^2 \over R} may incorrect. Why am I taught this equation in University if it is false...

Homework Statement What are the magnitud of G (gravitational constant) and the age of the solar system in CGS system of units and in seconds respectively? and what is the precision of these values and why? Homework Equations The Attempt at a Solution I found that the value of G in CGS system is...

Hello, I am taking a fluid mechanics class right now, so I deal a lot with water flowing through a pipe, and equations involving the density of the fluid. The problem is, that since I'm an engineering major, we use way too many english units. There is something inherent about non-SI units I...

I will study gravitation quantization(string theory or canonical quantum gravity),so I want to know what are the difficulties of gravitational quantization scheme.I know that quantization means that calculating commutator of quantum field operators via Poisson brackets.Are the difficulties being...

There is several things I am confused about with gravitational potential energy. So, first of all, shouldn't U=mgh always be written ΔU=mgΔh, because isn't that equation only dealing with differences of potential energies when close to the surface of earth? Second, with the equation U=-GMm/r...

hi everyone. I'm having trouble understanding the concept of proper time in general relativity. suppose we have some metric given by a fixed mass distribution, say schwarzschild or something (it's not important) and a test particle go over some path between two events A and B. if we want...

How much does gravitational pull on an object decrease if the distance is increased 10 fold for example? If planet x is stationary and part of a binary star system where star y is 1 AU away from it and star z is 1,000 AU's away, but also has 1,0000 times the mass, which star will exert more...

I have been learning that gravity has a negative energy associated with it. I've heard this stated a couple different ways, but I would like to understand a distinction. One line of thought declares that the potential energy of an object within a gravitational field is negative. Another line...