# gravity

### A How Long To 'FreeFall' Into TON 618 From ISCO

So I'm trying to help someone get an idea of the 'scale' of some of the most massive black holes, but, I'm at best a laymen when it comes to this...
Thread by: Daharen, Nov 13, 2018 at 12:10 AM, 1 replies, in forum: Astronomy and Astrophysics

### What will the FBD of 2 blocks being pulled look like?

1. The problem statement, all variables and given/known data Block A is on top of Block B, both are of equal mass and size. Block B is being...
Thread by: lyn83716, Nov 4, 2018, 7 replies, in forum: Introductory Physics Homework

### I What happens to the energy lost by photons in gravity?

After I read Martin_K's post of 4:14 Oct. 30 on the frozen image of an object just before it fell through a black hole's event horizon, the next...
Thread by: Hugh de Launay, Nov 1, 2018, 33 replies, in forum: Special and General Relativity

### A Calculation of the "lightness number" for solar sails

Hello, In the wikipedia article about solar sails the lightness number is mentioned and the calculation is the characteristic acceleration ac...
Thread by: Val---, Oct 30, 2018, 1 replies, in forum: Astronomy and Astrophysics

### B What would the universe be like with less mass and energy?

So I have sort of a conceptual question about the big bang and gravity. Imagine yourself in a universe, in which existed about the number of...
Thread by: Ethan Deibert, Oct 26, 2018, 2 replies, in forum: Cosmology

### I Trying to understand the entropy of different situations...

I just read a book by nuclear physicist Carlo Rovelli on the subject of "Time" and he says that 'entropy' is the only non-reversible process in...
Thread by: Mark Springer, Oct 24, 2018, 1 replies, in forum: General Physics

### B Gravity - Do atoms orbit humans ?

If the Earth orbits the Sun due to the difference in their mass and their distance, then do atoms like air particles orbit humans due to the same...
Thread by: DLeuPel, Oct 20, 2018, 5 replies, in forum: General Physics

### B The concept of a force lifting a weight and the work done

if I apply a force constant F=100N en $y$ direction to a body of mass 2kg, it is elevated 3m and I know that the force of gravity is in $y$...
Thread by: cristianbahena, Oct 2, 2018, 30 replies, in forum: General Physics

### B Feasibility of a L1 Gravity Swing Cold Launch?

At an L1 LaGrangian point between two bodies, one could - materials science notwithstanding - pit two of Newton's Laws (LM3,UG) against each other...
Thread by: hmmm27, Sep 15, 2018, 18 replies, in forum: General Physics

### B What if light were influenced by gravity?

How would the world be if light didn't travel in a straight line? I was wondering how it would affect life.
Thread by: Antonio dela Vinci, Sep 11, 2018, 31 replies, in forum: Special and General Relativity

### B What gives gravity its power to accelerate objects?

What is the physical property that gravity has that enables it to make an object go faster or, if it is resting on the ground, have weight? That...
Thread by: harrylentil, Sep 9, 2018, 8 replies, in forum: Classical Physics

### I Could a <1g acceleration vehicle escape Earth's gravity well

Hello, all - A question has come back to tickle my brain. Could a vehicle with less than 1G of thrust manage to escape the Earth's gravity well?...
Thread by: ckirmser, Aug 29, 2018, 31 replies, in forum: General Physics

### Gravitation sum related to Centripetal Acceleration

1. The problem statement, all variables and given/known data The distance between the centres of the earth and the moon is 60 times the radius of...
Thread by: Urmi, Aug 25, 2018, 5 replies, in forum: Introductory Physics Homework

### I Experiments about impact of mass in different areas

There's important experiments showing the equivalence of inertial mass and gravitational mass ( the Eotvos experiments), but I couldn't really...
Thread by: Felian, Jul 31, 2018, 3 replies, in forum: General Physics

### A Conversations on open problems in GR and Cosmology

I am making this thread to discuss interesting open questions in Gravity and Cosmology with people working in these or even relevant area....
Thread by: shahbaznihal, Jul 22, 2018, 1 replies, in forum: Special and General Relativity

### I Where is the prediction of the speed of gravity in the EFE?

Newton's law of gravitation cannot be compatible with relativity because the gravity from a massive object applies a force to all other masses...
Thread by: SamRoss, Jul 8, 2018, 4 replies, in forum: Special and General Relativity

### I About gravitational binding energy and kinetic energy

If a celestial body's kinetic energy (say, the Moon's) surpassed the energy necessary to exceed the gravitational binding energy (GBE), would said...
Thread by: GabrielLight, Jul 2, 2018, 11 replies, in forum: Astronomy and Astrophysics

### B 2 large objects of equal mass, Will they move each other?

Suppose there are 2 planets the size (diameter) of Jupiter. Both have the exact same mass. They are separated by a distance of about 10 times the...
Thread by: RobertSpencer, Jun 23, 2018, 4 replies, in forum: General Physics

### I Does gravitational field strength cause time dilation?

Hi I have 2 questions. There are 2 planets and one clock on each of them. One of them has a bigger gravitational field strength. And two clock...
Thread by: sawer, Jun 17, 2018, 6 replies, in forum: Special and General Relativity