All Questions
65
questions
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59
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Deriving expression for gravitational potential energy around a mass, $M$, using vectors
(I think my question will be somewhat related to this one: Deriving gravitational potential energy using vectors .)
I know the change in the potential energy associated with a conservative force, $\...
0
votes
1
answer
93
views
Potential energy involving both elastic and gravity
A block of mass $m$ is placed against an ideal spring as shown. Initially the spring (of force constant $k$) is compressed by a distance $s$. The block is then released and slides a distance d up the $...
0
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2
answers
67
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Minimum initial velocity to avoid collision [closed]
I'm having problem with the solution of this question:
Two material points with mass $m$ move along a horizontal axis subjected only to Newton's gravitational force law. At the instant $t_0=0$, one ...
- 237
0
votes
1
answer
98
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Triple integral gravitational potential between point and sphere [closed]
Problem for self-study: Gravitational potential between a point $\mathbf a$ and a uniform sphere, leaving out gravitational and density constants
$$
V(\mathbf{a})=\int\int\int\dfrac{1}{\vert\mathbf a -...
- 95
4
votes
3
answers
250
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Why is my answer for height negative?
Question is simple. A ball is thrown upwards with initial velocity $v_0$. How high does it go up?
Assume down is negative and up is positive and no air resistance.
KE at bottom = PE at the top:
$\...
- 109
0
votes
1
answer
22
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Finding the spring constant and magnitude of acceleration when it is dropped with the top attached to a ceiling [closed]
I've tried finding the potential energy by using PE = mgh then using PE = 1/2kx^2 to find k and setting PE = KE to find PE using velocity but neither is correct when finding the spring constant. I don'...
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-1
votes
1
answer
128
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From my reference frame, why does the Earth need a huge kinetic energy [$0.5M_E(11200)^2=3.75*10^{32}$ joules] to escape me? [closed]
I wake up screaming into the void, when I see the Earth almost touching me but going away from me at 11.2 $km/s$.
I don't remember what happened before I woke up. I faintly recollect being cannoned up ...
- 1,419
0
votes
2
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519
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Gravitational potential energy of an object on Earth compared to Moon
The gravitational potential energy of a $200\,\text{kg}$ satellite $3000\,\text{km}$ above the surface of the Earth is $U=-\frac{GMm}{r}=-8.5 \times 10^9\,\text{J}$.
Would the gravitational potential ...
- 372
5
votes
1
answer
114
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Insecurity about introductory classical mechanics [closed]
This is a problem I encountered, but not a homework assignment, I'm not only just looking for solutions here... This is my first time encountering questions like this, I'm sure you remember the first ...
- 287
0
votes
2
answers
50
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Orientation of gravity force in energy [closed]
My apologies in advance if this is a stupid question.
A 0.20 kg rocket in a fireworks display is launched from rest and follows an erratic flight path
to reach the point P, which is 29 meters above ...
- 179
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2
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3k
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Gravitational potential energy inside of a solid sphere [duplicate]
I am self-studying classical mechanics. I came across a problem which required me to calculate the gravitational potential inside of a sphere. I found in one of my textbooks that the potential energy ...
- 23
0
votes
2
answers
239
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Direct calculation of the gravitational potential inside a hollow sphere
I calculated the gravitational potential inside a massive sphere with constant density and got the result:
$$\Phi = -2\pi G\rho R^2 + \frac{2}{3}\pi G\rho R_p^2$$
Where $R$ is the radius of the sphere ...
- 16.6k
4
votes
2
answers
7k
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Why is the gravitational potential inside a hollow sphere same as that of the gravitational potential on the surface of the hollow sphere? [duplicate]
Gravitational potential inside a hollow sphere is given by $$V(r)=\frac{-Gm}{R}$$ Why is it the same as the gravitational potential on the surface of the hollow sphere, which is given by $\frac{-Gm}{R}...
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0
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44
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Why didn't we account for kinetic energy of two stars in conservation of mechanical energy
Two stars of masses 3×10^31kg each, and at distance 2×10^11m rotate in a plane about their common centre of mass O. A meteorite passes through O moving perpendicular to the star's rotation plane. In ...
1
vote
1
answer
949
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Cylinder gravitational potential
I have a question about infinite cylidner. I wanted to calculate a gravitational potential that it creates, but I've stumbled across some difficulties.
From Gauss's Law we know, that force on an ...
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