All Questions
9
questions
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answers
81
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Negative Energy and Gravity
Why do many science communicators say that negative masses fall upwards? Is it the same in the physics literature that they say that negative masses fall upwards?
In general relativity, things don't ...
- 11
0
votes
2
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119
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Since when did inertial mass and gravitional mass became equal?
If we think about inertial mass and gravitational mass as independent concepts and develop physics then we would know after a while they are only propotional (by precision we have by now). but it seem ...
- 1,409
2
votes
6
answers
804
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Is the gravitational force a phenomenon or a theoretical invention? [closed]
We use to say that gravitational force is a phenomenon. But since the theory of General Relativity replaced Newtonian gravitational force, how is it possible for a phenomenon to be replaced by a ...
4
votes
3
answers
472
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How does relativity explain Newton's apple? [duplicate]
You must have heard the anecdote about the apple falling on Newton's head that led him to come up with the concept of Gravity. A long time later, Einstein upgraded it to the General Theory of ...
- 91
2
votes
1
answer
31
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How to resolve this asymmetry in an example for the weak equivalence principle?
I am trying to unknot an obvious error in my understanding of the following example:
Fact 1: An observer on the moon watches a tiny ball of uranium and a tiny ball of iron fall. Both fall fall at the ...
0
votes
3
answers
95
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How can weight be equal in the equivalence principle?
According to Einstein, weight will be the same as here in earth in a rocket going at 1G far from gravity fields. If we propulse an object here it will feel two forces, F=mg and F=ma of the thrust, but ...
user189508
0
votes
1
answer
225
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A proof that gravitational and inertial masses are equal
Can't ' Gravitational mass equals inertial mass ' be proved as below? :
A particle is falling in a uniform gravitational field $g$ experiencing a force $m_gg$ ($m_g$ is its gravitational mass)
In its ...
- 1,270
1
vote
4
answers
159
views
Gravity, falling bodies, and the equivalence principle
Why is that bodies in a box accelerating uniformally in space that is sufficiently removed from gravitational fields fall identically to bodies in a box located in a homogeneous gravitational field (e....
- 85
8
votes
5
answers
6k
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Is it correct to say that falling object are standing still?
As I was browsing youtube I came across the BBC video "Brian Cox visits the world's biggest vacuum chamber - Human Universe: Episode 4 Preview - BBC Two"
He drops a bowling ball and a feather in a ...
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