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Questions tagged [newtonian-gravity]

The Newtonian model of gravity in which the force between two objects is given by GMm/r^2.

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Time for two masses to collide in space [duplicate]

Take two equal masses $m_1=m_2=m$, separated by a distance $r$ in space. The potential energy of the system would be $$U=-\frac{Gm^2}{r}$$ When they collide the total kinetic energy is $$K=mv^2$$ ...
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Find gravitational force of a point that moves along an ellipse [on hold]

A point with a mass of 20 g, that moves under the force of gravity to a fixed center according to Newton’s law of gravity, moving along a complete ellipse with 10cm and 8cm axes for 50 seconds. Find ...
61 views

What do we understand by a force being central?

Gravity is said to be a central force. But the resultant force field of multiple bodies is no longer central as it has many attraction points. My Doubts: Is the idea of a force being central ...
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Comparing Theory of Relativity with Newtonian gravity [duplicate]

How does Einstein's General Theory of Relativity compare with Newtonian gravity? How does the curvature of spacetime affect both gravity and the path of light in a planetary system?
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What would happen if one tried to lift an object that wrapped around the Equator?

Imagine a man-made object, let's say a dumbell, that was so long it wrapped around the Equator. Never mind the extreme difficulty of manufacturing such an object, let's assume it could be done. Let's ...
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Is Upside-down Racing Possible?

Based on the calculations I have done, upside-down racing seems to be possible. But in my mind, and certainly others too, it seems outlandish and impossible. Here is what I have come up with, please ...
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Physical reason for $T^2=a^3$ when $T$ is in years and $a$ is in AU

Kepler's third law states $$T^2\propto a^3$$ When $T$ is in years and $a$ is in AU, the proportionality constant becomes $1$. This can't be a coincidence; I would like to know the physical reason for ...
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Has the gravity a negative value?

We all know that the acceleration of the gravity is equivalent to 9.81 m/s². But the gravity attract everything that have a mass (everything as far as i know) to the center of a planet. As an ...
48 views

A heavy ball on a thin sheet of paper

If we keep a heavy metallic ball on a thin sheet of paper the paper is torn and the ball drops. But according to Newton's third law of motion every action has an EQUAL and opposite reaction. So when ...
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Will a man falling from a great height and a man lying on ground exert same amount of force on the earth?

Suppose in a situation there is a man falling from a height, when he falls from a height and touches the ground then he applies some force on the ground which is equal to his weight, and in another ...
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How would gravity affect a flat object with a slightly larger area than Earth's surface area, but lower in mass?

Imagine a flat object slightly wider than the Earth's surface area whose mass is much lower than that of Earth. If it landed on Earth, would the curvature of gravity bend it, or possibly even break it?...
50 views

If a ball is kept on the table, then what forces are being exerted on it?

If a ball is kept on a table then there is gravity acting on it as well as a normal reaction force by the table on the ball. But as both the forces are being exerted on the same object i.e. the ball, ...
131 views

Can Newtonian gravity be quantized?

Today, nobody knows how GR is truly supposed to be married with QFT. As a result, the standard model as it is typically presented does not include gravity. Could it be modified to include Newtonian ...
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Satellites orbiting around any planet's [on hold]

Suppose a satellite is revolving around a planet with radius r. Now if we increase the value of r then the angular velocity and kinetic energy will decrease, but the total energy & potential ...
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Y the relation among centripetal, centrifugal and gravitational force exerred on the moon is different from an object on the earth surface?

I read that since the earth vid rotating on its axis ,an object on the earth surface experiences a centrifugal force because the object is also moving around the earth's axis.So,that centrifugal force ...
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Difference between the work done by three masses on different situations

We have 3 particles, with mass $m_{i}$ What's the difference between: i) Putting each one in a positión $x_{i}$ one by one, and ii) Putting the three at the same time in positions $x_{i}$, in both ...
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What would be the distances between compressors part of a gas pipeline from Earth to the Moon?

This paper, acquired from this question about tethers on the Moon, describes LADDER, a mission to deploy a Lunar Space Elevator [LSE]. The space tether, made of Zylon fiber, would be 264,000 km long, ...
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Inextensible filament structure in gravitational field

Let $\gamma$ be a curve lying in a gravitational field with each point moving as an independent point mass. Formally, \begin{equation} \partial^2_t \gamma(u, t) = -\nabla U(\gamma(u, t)), \end{...
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What is the strength of gravity compared to electromagnetism?

I would like to know the strength of gravity as compared to electromagnetism. Im not looking for their classical constant values. It can be compared by saying i.e. gravity is a million billion times ...
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What is the effect of charge of Sun induced on the Earth as compared to gravity?

As we know gravity is a less attractive force than the for of electric and magnetic fields. My question is where does the effect of magnetic field go while gravity has pull on earth. At this point ...
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How does this toilet lid work?

After further reflection after closing the lid on my toilet, I noticed it exhibited a behaviour that I can't explain. When you let the lid fall, it falls at a constant speed regardless of its angle. ...
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In a Bose-Einstein condensate, do the cooled particles lose weight? [closed]

If the elementary particles are cooled, they lose a weight?
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How to derive “a blob of water in space becomes a sphere” analytically? [duplicate]

I'd like to understand better the assertion that planets are spheres because of gravity. The thing which I believe is true, but don't completely get, is that any arrangement of a sufficient number of ...
58 views

What is the maximum theoretical efficiency of conversion of potential energy to kinetic energy and vice-versa?

Am looking at different techniques available for identifying sources of energy. As part of it, have the following question : What is the maximum theoretical efficiency of conversion of potential ...
33 views

Questin on Motion in Gravitational Field

I just feel like I don't fully understand the following multiple-choice question despite the fact that I got the answer (which I still don't know if it's correct or not). "An astronaut is standing ...
59 views

Creating a Gravitational 2-body simulation

I am trying to create a simulation for a gravitational 2 body problem. But I am kind of having trouble to define the equations that can be solve numerically. From an inertial frame I defined the ...
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Moon causing tides violates conservation of energy?

It is a simple fact that the moon causes tides in the earth. But these tides seem to be a violation of the conservation of energy. Why exactly would this be? Well think of it the way I am thinking ...
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What can generate a larger gravitational fiel than the earth?

From what I know of gravitational fields and our earth gravity always repel objects and any mass. But I was wandering if there were forces that can oppose the earth gravitational force.
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Newtons law of gravity universal?

Im a bit puzzled about the video from “One Minute Physics” claiming that Newtons law of gravity is not universal, but breaks down on very heavy objects and are not really confirmed on very light ones. ...
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5 Lagrangian points: why isn't there a line of stability between $L_1$ and $L_4$ and $L_1$ and $L_5$ respectively? [duplicate]

Given the 5 Lagrangian points of two large orbiting bodies: (from wikipedia), why isn't there a line of stability between L1 and L4 and L1 and L5 respectively (as depicted in red in the modified ...
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Measuring acceleration due to gravity in the lab

I am measuring the acceleration due to gravity in the lab with an electromagnet apparatus. My textbook says to take the average time for a number of falls (keeping the height constant of course). ...
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How to conceptualize Newton's apple?

I have no physics background, which is the genesis of my question. In pop-science, it is frequently mentioned that Newton's apple didn't fall toward his head, but rather that his head came up and ...
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In which situation(s), if any, would two balls of differing mass actually hit the ground at the same time? [duplicate]

This is a common example physics teachers use. As far as I know, it never actually holds true. There are point masses: A(light, eg. feather), B(heavy, eg. hammer) and, C(eg. the Earth). They are all ...
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The Normal Force

I have a doubt regarding the Normal force. Is it derived from Newton's Third Law of Motion? I feel like it might, but it is not always equal to the Gravitational Force. Please clear my doubt.
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*All* forces in stacked objects on ground

I want to reference the first answer to this previous question: How is an object kept on a table is at rest? First, the problem I'm actually working on is a mat sitting on the ground and a box ...
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Weight in an elevator accelerating downwards with $2g$

I am aware of the classical apparent weight physics but I am confused about what happens when elevator falls with greater acceleration than g say two g or something.if I calculate the normal force it ...
I stumbled across this page describing the energy of a given object in orbit. It describes 'total energy' as: $$E_{k} + E_{p} = E_{\mathrm{total}}$$ where $$E_k = \frac{1}{2}mv^2$$ and $$E_p = \... 2answers 94 views {}Can the gravitational constant G be calculated theoretically? [duplicate] In an answer to a previous post of the same question, it was stated that the gravitational constant can not be determined theoretically yet! From my perspective, the reason this is not yet possible ... 3answers 159 views Is gravity a factor for sustaining fusion? Does gravity affect a Fusion reactors ability to sustain a reaction? If so has there been any experiments done or planed for in space? Holding / maintaining shape might be a lot easier with less ... 4answers 128 views How does Newtonian Gravity explain the difference between the experience of 1G and zero gravity? Or can it? Humans can feel the difference between being on earth's ground, and being in space (zero gravity) This can be explained by general relativity, where in (1), force is applied by the ground upwards, ... 1answer 43 views In a binary system, why m_1 a_1 = m_2 a_2? In the center of mass coordinate, m_1 r_1 = m_2 r_2, which is straightforward. Yet in this detailed deviation of radial velocity page 27, it says that the r_1, which is the magnitude of the vector ... 1answer 54 views Express the total mass of the galaxy in solar masses I have the following problem: "The Sun has an orbital speed of about 220 km s−1 around the center of the Galaxy, whose distance is 28 000 light years. Estimate the total mass of the Galaxy in ... 1answer 54 views How massive does a satellite have to be in order to shift the earth's orbit around the sun? How massive does a satellite have to be in order to shift the earth's orbit around the sun? I am wondering how massive a satellite has to be in order to be able to shift the orbit of the earth by ... 0answers 29 views Kepler's law for comparable masses I've recently been studying about Kepler's 3rd law... I went through the modification of it when the orbiting masses are comparable in terms of their mass.It was almost symmetric with the one I learnt ... 3answers 163 views Why aren't gravity batteries everywhere? [closed] The problem of energy storage, especially with regard to renewables, remains unsolved. Or at least there do not seem to be any popular solutions. Why not gravity batteries? I love the idea, and ... 1answer 68 views Could a mass of osmium be used to create a 0g room on Earth? Is it possible for a super dense element (such as osmium) to cancel out earth's gravitational field, and create a room without gravitational acceleration? 2answers 64 views Do hot gasses actually weigh more than cold gasses in SR? I was reading: https://plato.stanford.edu/entries/equivME/#PhysMassEnerEqui Where they begin to discuss a weighing a relativistic gas against a cold gas. The idea is that the relativistic gas ... 0answers 62 views Weight at Poles and Equator Wrong? Recently, I was thinking about the acceleration due to gravity on Earth when I remembered that I was taught that you weigh less at the equator because a fictitious centrifugal force "throws" you off ... 1answer 100 views Newtonian limit of GR, geometrically! In this article, Wikipedia says that Ricci curvature represents deviation of the volume of a thin geodesic cone from the Euclidean value:$$d\mu_g = [1 - \frac16R_{jk}x^jx^k+O(|x|^3)]\,\,d\mu_{...
I am trying to calculate the mass of a planet by the following image I have the mass of the object, $2$ kg, and the radius of the planet, $5000$ km (also the gravitational constant $G$). My first ...