# newtonian-gravity's questions - English 1answer

2.697 newtonian-gravity questions.

### 3 The (Newton-Laplace-Ivory-Arnold) shell theorem in general relativity

It is well-known that Birkhoff's theorem and the classification of LTB spacetimes proves one version of Newton's shell theorem in the context of GR. Another statement in Newtonian gravity, often ...

### Question about the Normal Force exerted by Planet Earth in relation to centripetal force

I have the following question based on a paragraph from my Physics textbook (I am translating, so the result might not be the most elegant): It states that due to the centripetal force resulting from ...

### Tipping angle of a box

how do you calculate the tipping angle of a box? That is the maximum angle a which a box can reach before tipping over. help, please!

### If there were two equal masses with one mass in the middle which way would gravity pull it?

4 answers, 786 views newtonian-gravity equilibrium stability
If there were two masses with a third exactly in the middle of those two, which way would the middle mass be pulled?

### Why is the Earth not an exact sphere and what makes it bulge at the equator? [duplicate]

In chapter 7 of the Feynman Lectures Volume 1, Feynman explains that the Earth is round due to gravitation as everything attracts everything else. He also says that it is not an exact sphere since it ...

### 9 How do we know that Earth is not perfect sphere?

I've just read here that: Equatorial radius = 6378.16 kilometers. Polar radius = 6356.78 kilometers, so the difference in circumference is 71.1 kilometers. It is not a perfect sphere, but kind ...

### -4 Why two balls of different mass dropped from the same height hit the ground at the same time? [duplicate]

2 answers, 54.422 views newtonian-gravity everyday-life
When two balls of different masses are dropped from equal height, they reach the ground at the same time. Can anyone explain this in terms of physics?

### 2 Why gravitational constant $G$ is used to calculate gravity between objects?

I have recently read about newtons law and i dont seem to understand why G is used. what is the logic behind G?

### -2 What is difference between 9.8 N (Kgwt) and 9.8 m/s^2 (g)?

What is difference between 9.8 N (Kgwt) and 9.8 m/s^2 (g)? What is difference between kg weight and gravity? I am not so good in physics so please explain in a lot of detail (but sorry for this silly ...

### 1 Infinite force in Newton's law of gravitation

2 answers, 45 views newtonian-gravity singularities
Newtons universal law of gravitation states that $$F=\dfrac{GMm}{d^{2}}$$ where $d$ is the distance between the center of mass of the two masses. Now a ring's center of mass is not in the ring. So ...

### 1 Force and momentum of water striking a water wheel?

Imagine water striking a water wheel. We can find the torque applied by calculating the force of the water and multiplying by the distance from the center. To calculate force, we can use the formula ...

### 4 Variation in measurements of $g$ on the Earth's surface due to the Moon's gravity

A book, Exercises for the Feynman Lectures on Physics, has recently been published. It consists of homework problems to provide practice with the techniques and concepts used in the famous Feynman ...

### -1 Can a tunnel through a planet be used as a power generator?

Assuming that it were possible to do so, if a tunnel from one side of a planet to the other were lined with copper wire, could dropping magnets down the hole be used to generate power?

### Angular Acceleration of a Pendulum

I am trying to work out the mathematics behind the design of an old mechanical brake tester. The device sits in the passenger foot well of a vehicle and tests the brake efficiency. The device is ...

### 6 Relative size of the 2 tidal bulges

3 answers, 1.065 views forces newtonian-gravity tidal-effect
I am interested in making a simplified model that represents only the effect that the moon has on Earths tides. In this model I am going to assume that the earth is completely spherical (with no ...

### -1 Calculating ringworld self-gravitation

I have built a ringworld calculator that gets around lack of strength by adding in a non-rotating counterweight to balance the force applied by the spinning habitable ring. For small rings with ...

### 7 Can Newton’s law of gravitation be derived from Coulomb’s law? [duplicate]

I’m casually learning physics and have noticed that Newton’s law of gravitation and the electrostatic force formulas look similar. I’ve asked this question before but would really appreciate another ...

### 20 Is Newton's universal gravitational constant the inverse of permittivity of mass in vacuum?

Is it possible to consider Newton's universal gravitational constant, $G$, as inverse of vacuum permittivity of mass? $$\epsilon_m=\frac {1}{4\pi G}$$ if so, then vacuum permeability of mass will be:...

### 13 Is there a way to fill Tank 2 from Tank 1 through Gravity alone?

2 answers, 21.995 views newtonian-gravity water flow fluid-statics
I am a newbie in water system design but I am currently faced with the exact situation below on my land, and I need to know whether gravity alone is sufficient in order to fill Tank 2 from Tank 1, as ...

### 5 Boundary conditions in Poisson's equation for gravity

2 answers, 235 views newtonian-gravity boundary-conditions
Say we want to calculate the gravitational potential everywhere around(outside) a solid, circular, right cylinder. We want to use Poisson's equation for gravity for that (Laplace(U) = -4*pi*density ...

### 5 Does gravity affect water permeability?

Suppose I have an approximately rectangular prism composed entirely of folded paper. If I place 600lbs on top of these rectangular sheets of paper, the paper should compress. How does this affect ...

### Gravitational Potential Energy and Zero Points

I have two questions. 1) The first one has to do with the formula for deriving Gravitational Potential Energy. I learned that, for the derivation of Gravitational Potential Energy given large ...

### 21 Gravity in other than 3 spatial dimensions and stable orbits

I have heard from here that stable orbits (ones that require a large amount of force to push it significantly out of it's elliptical path) can only exist in a three spatial dimensions because gravity ...

### Problem based on Gravitation [closed]

A rocket is launched vertically from the surface of the earth with an initial velocity of 10 km/s. How far above the surface of the earth would it go? Radius of the earth = 6400 km; g=9.8 m/s^2. ...

### 1 newton's cradle with 2 balls dropped from same height at same time

I'm creating a logo and want it to be as exact as possible. The logo idea is a "Newtonian cradle", but with only 2 balls and on straight steel wire (can't be bend). What would happen if I dropped ...

### -1 Can Newton’s law of gravitation and electrostatic force be related? [duplicate]

I’m very new to physics and have noticed that Newton’s law of gravitation and the electrostatic force formulas look similar. Is it possible they are related? Can the charge of particles be interpreted ...

### 1 Would a Lunar space elevator only be stable if it passes through Earth-Moon L1 or L2?

I understand that space elevators are extremely hypothetical (bordering on pure fiction), but they are supposed to be theoretically possible. My questions is about what longidtudes a lunar space ...

### Gravity’s effect on a vertical spring-block simple harmonic oscillator

I just found a question in my textbook which asked how the period of the vertical oscillation will change if the spring and block system is moved to the moon, and the gravity due to acceleration is ...

### Scaling of force between cubes? [closed]

I found an interesting problem online which has been confusing me for quite a while. Basically, two solid cubes of side length $a$ touch each other along one of their faces, and I am to find how many ...

### 3 Projectile Path Farther Away From Earth

I was hoping to get help with both a specific example and a general idea of how to do the problem. Here's my current understanding, which may or may not be correct: When objects are thrown from a ...

### 3 Understanding what it means that gravitation is proportional to the product of the masses

Newton's gravitational law states that $F = G*\frac{M*m}{d^2}$ Intuitively it means that the greater the masses, the stronger the force, but it is more precise than that, it is proportional to the ...

### 9 The converse of Newton's shell theorem

The shell theorem states that a spherically symmetric body $S$ of mass $m$ has a gravitational field identical to that of a point particle $P$ of mass $m$ located at the center of $S$. We can ask the ...

### -1 Does Newton's Third Law apply to gravity? [duplicate]

Newton's third law states that whenever a force acts on you, you act on it with the same force, just with an opposite direction(except it's stated a little fancier). Now if an apple is falling through ...

### What is going on in the system? How are the formulas $mg \sin(x)$ and $mg \cos(x)$ derived?

When a load is resting on an inclined plane, there is force $mg \sin(x)$ that's vertical to the inclined plane and force $mg \cos(x)$ horizontal to the plane acting on it like this: My textbook says ...