All Questions
Tagged with newtonian-gravity energy
125
questions
2
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1
answer
72
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Gravitational collapse - proof that energy dissipation is required?
As an undergraduate, I took a short course on astrophysics, where I encountered the Jeans mass. This is the critical mass for a spherical cloud of interstellar gas above which the cloud is predicted ...
- 317
0
votes
1
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79
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Where am I wrong in proving that force perpendicular to motion increases speed and kinetic energy? [closed]
Lets think of a helicopter flying at some height $h$. It throws a food packet to a person on the ground from air. Let's neglect the air drag.
The food packet is thrown only with some velocity $v_x$ in ...
- 85
2
votes
2
answers
111
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Why do higher objects have a greater force?
We did an experiment in class today using a spring scale, a plastic bag, and a variety of other objects. Essentially, we attached the bag to the spring scale and measured the force, in newtons, of ...
- 539
-2
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2
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158
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Thought experiment: Where does potential energy come from if matter is created from energy?
Let's do a thought experiment:
Assume that I have a machine that can convert energy into matter with 100% efficiency i.e. it can create any amount of matter in a small space so long as I pay it's ...
- 121
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0
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71
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Can the gravitational singularities of black holes be solved by potential or self-energy?
In Newtonian Mechanics, the energy density of gravitational field is negative in comparison with the positive energy density assigned to mass density, meaning that that the total positive energy of ...
- 466
1
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1
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28
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Describe the decrease in potential energy if two forces are acting on it one conservative which is greater than other applied by us in opposite dirn [closed]
So imagine this situation.
An object is experiencing two forces, one due to gravity in downward direction and other applied by us in upward direction such that our force is less than gravitational ...
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-1
votes
3
answers
423
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How does gravitational potential energy work in a very large distance?
Consider a thought experiment (that I made when I was in high school) involving a universe with only two objects: a massive planet and a small asteroid. Initially, they are millions of light-years ...
- 109
0
votes
3
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108
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How does gravity do work to a horizontal projectile?
Suppose a ball is moving in a horizontal projection with some velocity $u_0$ in the positive $x$ direction. Here we see that although gravity is perpendicular to the velocity vector, it changes the ...
- 11
0
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0
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386
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Relationship between height and mass?
Objects with different masses are placeed on the horizontal surface of a table. The objects are then raised to different heights above the tabel. The gain in gravitational potential energy of each ...
1
vote
1
answer
330
views
How to calculate the energy in a hyperbolic orbit?
I'm recently reading a book about rocket science which involved orbital mechanics. I know that in an elliptical orbit, the energy $ E=-\frac{GMm}{2a}$, and therefore can get the vis-viva equation: $ ...
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12
votes
5
answers
2k
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Why is cycling easier while standing on the pedals?
On high slopes and rugged terrains, riding a bicycle while standing on the pedals is easier. Even though I cannot physically define what is "easy"; since it is a feeling that my body ...
- 12.5k
-1
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279
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Increase in the internal energy of the block-surface system due to friction [closed]
I found this question:
https://plainmath.net/force-motion-and-energy/13968-block-dragged-horizontal-surface-acting-degree-horizontal-displaced
and I'm trying to understand why he used this formula to ...
0
votes
2
answers
55
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Work done by gravity confusion
Say we had an object at height $h$ in a gravitational field, and of mass $m$, its GPE would equal $mgh$, now say we dropped it and it fell a distance of $h$, the work done on the object would be equal ...
- 195
0
votes
1
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48
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$N$-body simulation: total energy is conserved, but what about the energy of a specific particle? [closed]
It is clear that the total energy in a full gravitating $N$-body simulation should be conserved, but what about the energy of an individual particle? Is this not conserved, since the potential is ...
1
vote
1
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61
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How to find amount of energy which goes to heat in a system of damped springs in a gravity field?
I am writing a simple computer simulation of a system (in 2 dimensions), with several circular bodies. They all affect each other by their gravity and some of them are connected via damped springs (...
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