|
Glossary
Einstein's Principle of Equivalence
Galileo's Principle of Equivalence
states that the inertial mass and gravitational mass of
a body are equal.
- The inertial mass mi
determines how the body accelerates as a results of
the application of any force
(Newton's 2nd law)
- The gravitational mass mg
determines how the body "feels" a gravitational force
and how much of a gravitational force it generates
(Newton's law of gravitation)
En route to extending the Special Theory of Relativity
to include gravity
(culminating in the General Theory of Relativity),
Albert Einstein picked up on this fact and realised that
it implied that acceleration and gravity
actually cannot be distinguished.
This led to
Einstein's Principle of Equivalence
|
The Laws of Physics are the same in a uniformly accelerated
reference frame as
in a uniform gravitational field.
|
The whole of General Relativity rests on this fact.
The consequences of the
Principle of Equivalence include
- the effects of a gravitational force are indistinguishable
from those present in an accelerated reference frame
- there is an (accelerating) reference frame in which the
effects of gravity are not experienced (falling elevator)
- the path of light is "bent" by gravity
- clocks run "slow" under the influence of gravity
- gravitational "redshift" of light waves
- gravity effects anything carrying energy (E=mc2)
Links
|