All Questions
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How much kinetic energy would a star in a galaxy have if it fell to the center?
I want to calculate the speed, or equivalently, the kinetic energy of a star, if it had no rotational speed and fell from a given radius to the center of the galaxy.
I assume Newton's shell theorem ...
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1
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What happens if we define the gravitational potential zero point at a finite distance? [duplicate]
Two questions.
Can we, and if so how do we define the gravitational potential of a mass (say the sun) to be zero at a finite distance (say 1 light year)?
How does this change the gravitational force ...
- 47
1
vote
1
answer
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What energy is transferred into potential? [closed]
This question could be really out of the blue and might receive lots of downvotes, but bugging me quite a time and would appreciate your thoughts easily explained.
We know that when we do work against ...
0
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3
answers
76
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Gravitational potential energy definition
"Gravitational potential energy of a system of masses is defined as the negative of the work done by gravitational force in bringing the masses from infinity to that configuration" ~ the ...
2
votes
1
answer
96
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Infinite gravitational potential question
For this question I use Newtonian gravity only. Relativistic gravitational/kinematic effects are ignored.
It is known that the gravity surrounding a point particle of mass $M$ can be described by ...
user324471
2
votes
2
answers
238
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Intuition behind gravitational potential
Gravitational potential at a point is equal to work done in bringing a unit mass from infinity to a particular point
That was the text book definition
$$V_{p} = -\frac{GM}{r}$$
If we calculate $V_p$ ...
2
votes
2
answers
2k
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How to calculate eccentricity of a planet via energy?
The relative distance of a planet moving around the sun is found to be:
$$r(\varphi) = \dfrac{\kappa}{1+\varepsilon\,\cos(\varphi)} \quad \text{where} \quad \kappa = \dfrac{L^2}{G\,{m_p}^2\,m_s} \quad ...
- 462
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1
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71
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The gravitational potential at the center of a solid ball (confusion)
I came across this question during my physics class. Suppose we have a solid, spherical planet with mass $M$ radius $R$ s.t. the density of this planet is uniform everywhere, then what is the ...
- 115
1
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1
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555
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Gravitational potential inside and outside a spherical shell
Let $\Phi$ denote gravitational potential. This is an example from a book (Classical dynamics, Thornton-Marion). We assume a homogeneous spherical shell. The writer says: We integrate over $d\phi$ in ...
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2
votes
1
answer
365
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Gravitational potential energy defined as the work done on a mass
Our physics sir made us write that gravitational potential energy is the work done in bringing a mass from infinity to a point without acceleration, but I am confused because if acceleration is $0$ it ...
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2
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1
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Gravitational Potential Derivation
The definition of Gravitational Potential at a point is the work done per unit mass in moving it from infinity to that point. However the work is positive and if you perform the integral you get a ...
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2
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Is a *difference* of potential energy relative to a frame of reference?
If we consider an electrical field, or a gravitational field, and two points in this field, is the difference of potential between this two points depending of a frame of reference ?
It seems to me ...
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2
answers
1k
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What is the physical reason for why gravitational potential (or electrical potential) due to two masses at a point can simply be added algebraically?
The simple explanation that textbooks and the internet say is that "gravitional potential is a scalar quantity hence can be added algebraically".
However, I'm not sure if it is that simple. Take for ...
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-1
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1
answer
2k
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Relation between gravitational potential and gravitational field
The relation between gravitational potential and gravitational field is
$V_{r_2} - V_{r_1} = - \int^{r_2}_{r_1}\vec E\cdot d\vec r$
Where terms $V$ stands for potential and $E$ for gravitational ...
- 329
1
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0
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63
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How much electric energy is created by an 80kg man making a step at flat surface while walking at the normal speed (5km/h) [closed]
Even a rough approximation would be helpful. But of course a precise calculation would be great :). Thank you all in advance very much for your help!
By the way - do you have any suggestion for ...
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