# Questions tagged [newtonian-gravity]

This tag is for questions regarding the Newtonian model of gravity in which the force between two objects is given by $~GMm/r^2~.$ It is a natural phenomenon by which all things with mass or energy – including planets, stars, galaxies, and even light – attract one another. On Earth, gravity gives weight to physical objects, and the Moon's gravity causes the ocean tides.

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### Issue while understanding gravity/radius of earth graph [closed]

I have following question. What are my opinions? 1. Option 1 - This is incorrect. I think dotted line in option 1 from bottom to peak represents center to surface of earth. After the peak, line ...
1 vote
34 views

### Confusion in definition of Potential Energy

Potential energy is defined like this. $ΔP.E=-W_{AB}$. This means that the potential energy at point A minus potential energy at point B should equal the negative of the work done by a conservative ...
59 views

### Gravitational potential energy in Escape Velocity

From the derivation of formula of Escape Velocity we know that Minimum kinetic energy = Gravitational Potential Energy But in this circumstance, isn't it the value of gravitational potential energy ...
30 views

### Trying to understand Gravitational Field

I have learned that gravitational potential is defined as the amount of work done on bringing the mass from infinity to distance r. But what does that infinity signify in the definition, I mean like ...
37 views

### Electromagnetism in the Cavendish experiment [closed]

What are the best arguments that debunks the idea that the attraction between the masses observed in the Cavendish experiment is caused by electromagnetism, and not gravity?
39 views

### What would happen if I was swimming in a pool that fell several stories? [closed]

What forces would I be subjected to (and is there a depth at which I would likely survive), if I was swimming in a 12' pool at the top of a ten story building and the whole pool fell through the floor ...
1 vote
36 views

### Question on Gravity (Ring and Sphere) from JEE Mains 2021 [closed]

Find the gravitational force of attraction between the ring and sphere as shown in the diagram, where the plane of the ring is perpendicular to the line joining the centres. If $R\sqrt8$ is the ...
5k views

### Why are there so many objects perfectly orbiting each other? Isn't it infinitely more likely that two random objects crash/fly apart?

If, in free space, I throw two objects towards each other, they can either miss each other and fly apart (if the velocity is enough and there's not enough gravitational attraction between them), or ...
76 views

### Debunking flat earther's about Cavendish [closed]

Yes, I know it's useless to waste time with this kind of people because they will never accept reality, but I learn a lot from these types of discussions, so here it goes. Flat-earthers deny all ...
103 views

### Does this question require any calculus to solve? [closed]

So, I came across this question in a book, Two spherical bodies of mass $M$ and $5M$ and radii $R$ and $2R$, respectively are released in free space with initial separation between their centers ...
41 views

### Total energy of a rocket launch

I'm wondering how the total energy of a combined Earth-rocket system is conserved in a rocket launch? Before launch, kinetic and gravitational potential energy of the rocket are 0. It then launches, ...
1k views

### Observation of the effect of gravity on the motion of antimatter

In a recent paper (https://www.nature.com/articles/s41586-023-06527-1), the authors state that we find that the local gravitational acceleration of antihydrogen is directed towards the Earth and has ...
505 views

### Why does gravity cause objects to pull other objects with constant acceleration and not constant force? [duplicate]

I know that this may come off as an incredibly dumb question, but please hear me out for a while. Why don't objects just tug at other bodies with a constant force? Instead, why do they apply ...
63 views

### Sign of force for assumed $mgy$ gravity [closed]

If gravity force of earth is $mg$: if positive y is pointing upwards, then: $m\vec a = -mg\hat y$ and $\ddot y = -g$ if positive y is pointing down, then: $m\vec a = mg\hat y$ and $\ddot y = g$ If ...
27 views

### Electric constant and the Cavendish experiment [closed]

If I did the Cavendish experiment but accidentally used magnetic materials or materials that interacted electrically in some way, would I arrive at the result of the electrical constant, the ...
56 views

### Escape velocity work done problem [closed]

We derive the formula of escape velocity by using conservation of mechanical energy, where we consider that work done by external force is neglected. But to provide the velocity to send an object to ...
1 vote
77 views

### Can mass be negative? [duplicate]

like charge is fundamental property of matter which exist in both negative and positive aspect and help us to understand the electro-magnetism ,in the same ways would mass be negative ? in that ...
1k views

### What is the smallest known gravitationally bound system?

Recent discovery of a satellite orbiting Dinkinesh made me wonder how fragile that system must be. Based on the numbers and photos given by NASA, I estimate that binding energy of the two bodies is of ...
257 views

### Why do gravity and electricity sometimes obey inverse square laws over the same distance scale?

Is this a chance mathematical coincidence or is there a good physical explanation for it? 39 views

100 views

### Newton's 2nd law and gravitational law [duplicate]

I am studying the Newton's Law's of Motion, and really confused about one thing. I know that bodies of very small mass get attracted to our earth due to a force it exerts, due to its huge mass. So ...
Torque about centre of sun is zero. $$T=Ia$$ So angular acceleration is zero too, so angular velocity should remain constant. However it is not the case. Please tell where I went wrong.