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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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Please explain gravity? [on hold]

If spacetime is like an elastic plane holding planetary masses that sink into pockets creating "gravity" and planetary orbits around large masses, then how do we explain the "gravitational force" we ...
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4answers
34 views

Why does the GPE of an object always equal the work done?

I had a question that said, "If you do 100 J of work to lift an object over your head, what is the gravitational potential energy relative to its starting position? What would be its gravitational ...
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3answers
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Difference between center of mass and center of gravity

Let's consider a very tall building (g would be variable) which is rotating with the earth naturally. Now do the centrifugal force and the gravitational force act on the same spot? If not why does the ...
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3answers
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Why doesn't the Earth accelerate towards us?

According to Newton's third law of motion that states that every action has an equal and opposite reaction. So, if the Earth exerts a gravitational pull on us (people) then even we should exert a ...
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1answer
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How is the normal force on a banked track larger than gravity?

The formula of the vertical force of an object that is not accelerating up or down on a banked curve is: Ncos(θ) = mg There is also a centripetal force component which shows that the normal force is ...
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0answers
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How does a Foucault pendulum in an Earth-sized centrifuge precess?

Imagine replacing Earth with a centrifugal arm length Earth radius and rotating to produce acceleration g. How does a Foucault pendulum mounted on the end of the centrifuge move and why ? Ignoring ...
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1answer
33 views

Will the motion in both systems be same?

In my book, the discussion in SHM is mainly about a mass hanging vertically from a spring. But there are some exercises which contain questions which involves a mass attached to a spring and the whole ...
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3answers
50 views

Gravitional Potential Energy Formula Magnitude confusion

It is pretty intuitive that increasing the height or distance of an object and also increasing the mass of it increases the gravitational potential energy (GPE). Basically the question is asking, ...
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0answers
27 views

Mass hanging from spring in free fall

Q: A mass $m$ hangs from a massless spring connected to the roof of a box of mass $M$. When the box is held stationary, the mass-spring system oscillates vertically with angular frequency $\omega$. If ...
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1answer
54 views

How fast can we walk?

It has been a common observation that as and when we accelerate ourselves, there comes a point after which we cannot stay on the ground completely. I wanted to know whether we can find such a maximum ...
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0answers
23 views

Force of gravity [duplicate]

I want to know why isn't the moon fall on earth instead of floating on top or going around the earth without even falling on earth by the force of gravity on earth .
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0answers
33 views

What determines the direction of an object that has undergone the effect of a gravitational slingshot?

I just started researching this topic and therefore I do not know much about it. Nonetheless, I am still curious about what determines the direction an object takes after passing by a planet. I think ...
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0answers
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How to set setup of a torsion pendulum/balance physics experiment [on hold]

@Moderator: Per your meta data: "What about experimental physics and laboratory equipment? Physics is not just theoretical, and experimental physics is on topic here. This includes questions about ...
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0answers
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Constraints on the mass distribution within each body such that their mutual orbits are Keplerian?

The trajectories of two point masses with respect to their center of mass are conic sections or Kepler orbits. But what if the bodies have finite size with respect to their separation, and not ...
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2answers
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Calculation of Gravitational Collapse time

The answers to Gravitational collapse and free fall time (spherical, pressure-free) describe the calculation of collapse time for a gas. For the case of neutral hydrogen gas with number density $10^4$/...
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1answer
57 views

Negative Work done by gravity

When we lift an object from ground we say we did work on object . We also say that gravity has done negative work because we did work to overcome gravity . When we did work our chemical energy was ...
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0answers
34 views

introducing and measuring a torque field [closed]

let me introduce the context: I wrote a C++/SDL simulation for $n$-body-problems (simple linear interpolation of Newtonian gravitation and $F=ma$) my focus is on symmetrical starting condition $2^n$-...
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1answer
26 views

Is the Gravity Turn the most efficient way to put a spaceship into orbit?

The Gravity Turn is a maneuver used to put a spaceship from ground into orbit. It can be described as lifting the spacecraft vertically up, then tilting it towards the desired orbit by a small angle ...
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1answer
29 views

If three equal free masses $M$ are at rest at vertex of equlateral triangle of length $R$ at $t=0$.what is relation between position and time? [closed]

I need a equation describing relationship between position of particle and time.You can assume only gravitational interaction between masses.
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0answers
30 views

Gravitational Potential Energy of two particle system [closed]

Derive the expression of gravitational Potential Energy of two particle system{closed} by not assuming 1 particle to be rest.
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0answers
49 views

If gravitation force varied with $r^{-3}$ instead of $r^{-2}$ what would happen to Kepler's laws [duplicate]

2nd law wouldn't change as it is LCAM. 3rd Law would change. But I'm confused about first law. Does any body under influence of any central force move in an ellipse?Can anyone give a simple proof/...
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1answer
29 views

Effect of wheel location on center of gravity

So, my kids are in Cub Scouts and are racing in the Pinewood Derby for the first time. After a thorough read-through of the rules, there is nothing prohibiting a racer from shifting the rear axle (or ...
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1answer
25 views

Gravitational potential of a point due to hollow sphere [closed]

You may all have learnt about this. But don't you think that the $dE$ written above is of a point on that ring which is at a distance $z$ from point $p$. Then why we have taken $dm$ as mass of that ...
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1answer
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Gravitation problem [closed]

Two bodies A and B of masses $m$ and $2m$ respectively are kept a distance $d$ apart. Where should be a small particle be placed, so that the net gravitational force on it due to the bodies A and B ...
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2answers
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Why is the Moon's Centre of gravity different to its centre of mass? [duplicate]

All the places that I've seen an answer to this question simply state that it's because there is a stronger gravitational pull on the near side of the moon, facing the earth. But I'm wondering how ...
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1answer
57 views

Modification of Gravitational force's law and related problem

I'm facing a problem which states the following: Suppose that it is discovered that Newton's law of gravitation is incorrect and that the force $F$ on test particle of mass $m$ due to a body of ...
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1answer
47 views

If I drive East, how much lighter am I than if I drive West?

I'm at the equator. Suppose I am driving at x kph, in the direction of the Earth's rotation (i.e. due East), I presume that the force my vehicle exerts on the ground is less than when I am stationary. ...
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2answers
35 views

Which force described the “absolute” speed change of the moon in Newtonian mechanics?

In the world of "absolute" speed values in the Newtonian mechanics, the moon must move faster (i.e., must have a higher speed) if he travels with the earth (i.e., has the same velocity direction) than ...
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1answer
38 views

Acceleration: $G$ and $G$s difference

In some literature the acceleration is stated in Gs units. For example, "All structures shall be built to survive 15 Gs of launch acceleration". However, g-force sometime also stated in G units ...
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2answers
1k views

Shouldn't ball has to move in the circle even after cutting the rope by which it was attached? [closed]

Since the tension force is a central acting force, the torque on an orbiting ball about that center is zero. But if the rope is cut down during motion the torque would still remain zero. This would ...
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0answers
64 views

What is the gravitational force at the center of the earth? [closed]

According to Newtonian gravity, $$F=\frac{GMm}{r^2}$$If we are standing on Earth, then $r$ should be zero, so what is the gravitational force at that time? Similarly, what is the gravitational force ...
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2answers
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0answers
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Particles of mass 4m and m with velocity v are at infinite distances from each other in space centre of mass frame is not valid? [on hold]

Two particles of mass $4m$ and $m$ are at infinite distances from each other. They are left with a velocity $v$, hence their kinetic energy is positive. The initial distance between the two particles ...
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6answers
100 views

Potential Energy and Work [duplicate]

My physics textbook says when a rock is lifted gravity does negative work and increases the gravitational potential energy. My understanding of negative work implies energy is being removed when an ...
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2answers
70 views

Why cannot we go in outer space with constant speed?

Sorry if this question is very childish for experts here. This was the question I had in school and years later it has resurfaced. I did some google search but getting the same equations of ...
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0answers
33 views

Is the total mechanical energy of a satellite constant, regardless of its orbital radius?

If a satellite moves outwards into an orbit that is at a greater distance from the centre of Earth, work has been done. As work is the sum of the change in kinetic energy and gravitational PE, has the ...
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0answers
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Gravitational force on a point mass due to a ring of mass

I tried to work out a problem related to gravitational force due to rings. But it seems like I've got some misunderstandings in the theory. A point of mass M is on the axis that runs through the ...
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3answers
118 views

If a satellite moves towards Earth, is negative work done against the force of gravity?

A bit confused here - if a satellite approaches Earth, its displacement is in the same direction as the gravitational force (towards the centre of rotation). Therefore, gravity is doing positive work? ...
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6answers
130 views

How is it possible to escape a gravitational body? [duplicate]

The velocity required to escape a gravitational body is termed escape velocity. But how is it possible for any object to escape a body if it's gravitational field acts over an infinite range, so the ...
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2answers
37 views

Constant gravitational acceleration $g$ and energy

I've been taught the $g$ is constant for different masses and that if I were to drop a heavy object and a light object from the same height then they would reach the ground at the same instant with ...
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2answers
35 views

How does gravitational attraction relate to weight? [duplicate]

I understand that gravitational attraction is the attraction of a particle by another particle or matter, which in this case is the earth. But I don't understand why this (gravitational attraction) is ...
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1answer
17 views

Will water spill out of filled capillary tube, if raised from water?

if to raise a filled capillary tube from the level of water, will the inside will spill out? or will it keep stuck inside? imagine a capillary tube put in water, the water rises inside the capillary ...
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0answers
23 views

Why do bodies fall identically in uniform acceleration and uniform gravitational field? [duplicate]

In his reformulation of Einstein’s Elevator thought experiment, James Robert Brown (1993) says that an observer in a uniformly accelerating spaceship in space (free of gravitational effects) will see ...
1
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1answer
47 views

Lagrangian Equation of Motion for Planetary Orbit in a Single Plane

Assume that a mass $m$ is in a gravitational orbit around a much larger mass $M$, as in the case of the earth revolving around the sun. Also, assume the motion is constrained to a single horizontal $...
0
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2answers
15 views

What is meant by “instantaneously aligned” with regards to rotating reference frames/coordinate axes?

I'm trying to understand a set of lecture notes I found online from MIT which describe the derivation of the equations of motion for an object in a rotating reference frame, this is for an essay on ...
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4answers
111 views

Gravity, falling bodies, and the equivalence principle

Why is that bodies in a box accelerating uniformally in space that is sufficiently removed from gravitational fields fall identically to bodies in a box located in a homogeneous gravitational field (e....
0
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3answers
61 views

What's the difference between gravitational attraction and weight? [duplicate]

What exactly is gravitational attraction? In my textbook it was quoted " all objects both tiny and large objects are attracted to the earth. This is known as gravitational attraction, or the force due ...
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2answers
75 views

Do comets and meteors attract artificial satellites while passing by?

What will be effect on artificial satellites when comets or meteors come close or pass by?
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1answer
263 views

Wave particle duality and gravity

Is a particle's center of gravity at the center of its wave function or is it where we would measure the particle to be? When we measure a particle does its center of gravity shift to where the ...
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0answers
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Equations of motion due to gravity [duplicate]

This question has probably been asked before, but I couldn't immediately find anything with a search. Two masses of $m_1$ and $m_2$ kgs are in space separated by a distance of $x$ meters. They now ...