All Questions
8
questions
0
votes
1
answer
546
views
Gravitational field strength between equipotential lines
Is the gravitational field strength between two equipotential lines the same at all distances? For example, in the image, does point P experience the same gravitational field strength as a point ...
- 15
2
votes
1
answer
173
views
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 ...
- 31
6
votes
5
answers
3k
views
What is $R$ in the formula for escape velocity?
From the escape velocity formula
$$v_e = \sqrt \frac {2GM}R.$$
Some sources say it is the distance between two objects with mass $M$ and $m$.
Some examples I have read, only used radius of the $M$. ...
- 443
1
vote
2
answers
227
views
Collisionless Boltzmann Equation [closed]
I am looking at a derivation of the collisionless Boltzmann equation and I am unsure of how they got from one line to the next, so if someone could explain the step to me that would be much ...
- 57
1
vote
4
answers
944
views
Which would require less energy to rub the black board?
I have been thinking about a problem that would give teachers and students that rubs blackboard the optimum way to rub the chalk off the blackboard.
The problem is as follows:
"A man is going to rub ...
0
votes
2
answers
319
views
Gravitational potential and intensity
Why don't we calculate gravitational field/intensity of a point due to a disc directly? We first calculate the potential then calculate the field by differentiating with respect to $dr$. Why don't we ...
- 36
0
votes
0
answers
83
views
What is "W external" and "W internal" in Energy conservation law?
When I solve the energy conservation problem, I am confused when I have to make the term positive or negative.
For example, someone throws a ball right up to the ground with velocity, $v$. The ball ...
- 101
2
votes
0
answers
389
views
General potential of rotating system
I'm new here at the physics site, and not really that deep into the area of which i'm going to ask a question about now.
Therefore please feel free to ask clarifying questions.
I'm trying to deal ...
- 21