All Questions
Tagged with newtonian-gravity reference-frames
228
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Why is there a downward apparent force on an object accelerating upwards in an elevator?
In an upward accelerating elevator with acceleration a, from the inertial reference frame, a normal force equal to N= m(a+g) will be acting on the object inside the elevator of mass m. Now, for normal ...
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Direction of centrifugal force at different latitudes
Why is the direction of centrifugal force acting parallel to the equator rather than perpendicular to the centripetal force on 3D rotating spherical objects like the Earth?
I'm having trouble ...
- 97
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Free fall of two point particles in general relativity vs. Newtonian mechanics
In general relativity (GR) the equation of free fall of two point particles which start from rest at some finite distance $r_i$ is strikingly similar to the equation of free fall in Newtonian ...
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5
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Why don’t we feel weightless on airplanes?
If we feel weightless because there is no contact force acting on our bodies. Then why are there no contact forces for people in the international space station but there is for people on airplanes?
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Does the Earth orbit an ellipse or the barycentre of the Solar system?
I'm taking physics lessons in university and my professor described the Earth's orbit as en ellipse, where one of the focal points is the Sun (1st Kepler's law).
However, this doesn't make much sense ...
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4
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Gravitational potential energy of a two-body system
We say the gravitational PE of a system is $-GMm/r$. This is for a constant gravitational field. But, when we try to calculate PE for a two-body system, the distance the body moves is not the same as ...
1
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2
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462
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What what will happen to the height of the Mercury column in a barometer when it is accelerated upwards?
What will happen to the height of the Mercury column of a barometer when the barometer is accelerated upwards assuming the value of g does not change with height?
I think the height will remain same ...
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2
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Difficulty understanding why acceleration of free fall is lower at the equator than the poles
I have been told that the acceleration of free fall is lower at the equator than at the poles, and that this has to do with the fact that at the equator, you are moving with circular motion so ...
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Why is Microgravity called "Microgravity"?
I find the term "microgravity" to be misleading, how was it coined?
NASA provide this definition:
Microgravity is the condition in which people or objects appear to be
weightless. The ...
- 457
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2
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509
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In a hypothetical ring-like space station, would an astronaut feel a centripetal force?
This is the classical example used in newtonian mechanics to explain centrifugal force. I understand that on the space station itself there is a centripetal force $\vec{F}_{centripetal} = \frac{mv^2}{...
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Weightlessness during free fall and in free space, are they same?
Einstein's thought of a person under free-fall and when suspended in free space with no forces acting, will feel the same way.
On Walter lewin's lecture on free fall he told free fall is when only ...
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3
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How does $\frac{mv^2}{r} = \frac{GMm}{r^2}$ work if both planets attract each other?
According to this and this, both posts describe the fact that the earth and the moon are attracting each other due to gravitation.
The gravitation force is $\frac{GMm}{r^2}$.
However, I am not able to ...
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Do we have to care about the force from the Milky Way black hole while analysing the Solar system from its Center of Mass frame?
And also while analysing Earth's spinning motion about its center? Do we have to care about the forces from the giant Black Hole at the center of Milky way?
I guess we would have to take the Black ...
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Some concepts of circular motion between man and the Earth？
I know it's a regular question, but I'm having a problem with the concept of circular motion.
Intuitively, the earth and people have the same angular velocity，It's because people are standing on the ...
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Why is the moon in free fall? Isn't there a centrifugal force acting on it? [duplicate]
An object is in free fall when the force acting on it is exclusively gravitational. But why then is the moon in free fall? Isn't there a centrifugal force acting on it?
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