All Questions
Tagged with gravity newtonian-mechanics
317
questions
62
votes
5
answers
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Why is the Moon considered the major cause of tides, even though it is weaker than the Sun?
You have likely read in books that tides are mainly caused by the Moon. When the Moon is high in the sky, it pulls the water on the Earth upward and a high-tide happens. There is some similar effect ...
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43
votes
5
answers
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views
If the gravitational force were inversely proportional to distance (rather than distance squared), will celestial bodies fall into each other?
If gravity was inversely proportional to distance, will the dynamics of celestial bodies be much different from our world? Will celestial bodies fall into each other?
- 589
31
votes
6
answers
2k
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Can I survive a free fall using a ramp and a rope?
Can I survive a free fall by carrying a very light and resistant ramp using a rope?
Note: lets assume the ramp is a little bit heavier at the bottom and I am very skilled at making it always land ...
- 430
22
votes
5
answers
7k
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What helped Einstein to provide a more accurate description of gravity than Newton?
Newton's explanation of gravity as an attractive force seems to have been superseded by Einstein's explanation of gravity as warping of space-time. Was there any advances in math and science that was ...
- 431
22
votes
4
answers
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Ball thrown faster than terminal velocity [duplicate]
I recently read about the property of terminal velocity for objects and I got a question when doing so.
If from a very tall building I throw a ball faster than terminal velocity downwards, will the ...
- 1,289
19
votes
3
answers
5k
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How do crocodiles jump?
In a video (Here), I saw crocodiles jump vertically about three meters without using any solid surface. The wonderful thing is that when they start to jump, their vertical velocity is approximately ...
- 425
19
votes
1
answer
11k
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Why don't lakes have tides?
There's a tidal effect that we can clearly observe in oceans, which is the effect of gravity from the Sun and the Moon. If gravity affects everything equally, why don't lakes have tides?
- 2,737
16
votes
6
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Why can light (photons) bends in a curve through space without mass? [duplicate]
I've heard that light can form a curve if they travel near high-mass stars or even a black hole with strong gravity. Which is according to this Newtonian formula
$$\large F_{g}=\dfrac{Gm_1m_2}{r^2}.$$...
13
votes
3
answers
717
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Leading-order cause of diurnal (not semidiurnal) variations in $g$?
The following graph shows the result of a very impressive differential measurement of the gravitational field in Boulder, Colorado, over a period of a couple of days.
Floris got it from a description ...
user4552
12
votes
2
answers
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Gravitational potential energy of any spherical distribution
The general formula to get the potential energy of any spherical distribution is this :
\begin{equation}\tag{1}
U = - \int_0^R \frac{GM(r)}{r} \, \rho(r) \, 4 \pi r^2 \, dr,
\end{equation}
where $M(r)$...
- 7,592
9
votes
3
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If $F=ma$, how can we experience both gravity and a normal force even though we are not accelerating?
As I sit in my chair, I experience a gravitational force pushing me into the chair and I'm also experiencing the normal force of the chair pushing back at me so I don't fall. According to Newton's ...
- 121
9
votes
2
answers
2k
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Non-Constant Acceleration due to Gravity
Recently, I had the first physics lab for my university physics course. This lab was fairly simple, as we were merely using a computer and a distance sensor to graph the position, velocity, and ...
- 93
9
votes
1
answer
614
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Marvin the Martian vs. the Death Star: how much energy will they actually need to disintegrate the Earth?
According to a detailed analysis by Dave Typinski, Marvin the Martian’s Illudium Q-36 Explosive Space Modulator will require $1.711 \cdot 10^{32}~\text{J}$ to shatter the Earth into a gravitationally ...
- 360
8
votes
5
answers
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Zero gravity means zero friction?
The frictional force acting on a body placed on a horizontal plane is
$F=\mu{R}$
where $R$ is the normal reaction and is equal to weight of a body in this case. And $\mu$ is the coefficient of ...
7
votes
3
answers
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Tidal force on far side
I have a question about tidal forces on the far side of a body experiencing gravitational attraction from another body.
Let's assume we have two spherical bodies $A$ and $B$ whose centers are $D$ ...
- 3,433