- #1
vin300
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The equivalence principle is a straightforward application of Newton's third law, isn't it? There's nothing new in it
What is the difference between the equivalence principle and Newton's third law?
- Thread starter vin300
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In summary, the equivalence principle is a fundamental concept in physics that states that the effects of gravity and acceleration are indistinguishable. It was first proposed by Albert Einstein in 1907 and is important in understanding the relationship between these two forces. The principle has been tested through various experiments and although it is a fundamental concept, there are some exceptions to it, such as near a black hole or in the presence of external forces.
- #2
tiny-tim
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Hi vin300! 
Do you mean Newton's second law (F = dmomentum/dt)?
But it applies to light, and it gives twice as much deflection as Newton does.
vin300 said:
Do you mean Newton's second law (F = dmomentum/dt)?
But it applies to light, and it gives twice as much deflection as Newton does.
- #3
Entropia
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While the equivalence principle may seem to be a straightforward application of Newton's third law, there is actually a fundamental difference between the two concepts. Newton's third law states that for every action, there is an equal and opposite reaction. This law applies to interactions between two objects with different masses, such as a person pushing against a wall. The wall exerts an equal and opposite force on the person due to its larger mass.
On the other hand, the equivalence principle applies to the effects of gravity on objects with different masses. It states that in a uniform gravitational field, the gravitational force experienced by an object is independent of its mass. This means that in the absence of other forces, all objects will fall towards the ground with the same acceleration, regardless of their mass. This is a different concept from Newton's third law, as it applies to the force of gravity rather than interactions between two objects.
Furthermore, the equivalence principle also extends to the effects of acceleration and gravity on objects. This means that an object undergoing acceleration in a uniform gravitational field will experience the same effects as if it were in a stationary gravitational field. This principle has major implications in the field of general relativity, where it is used to explain the relationship between gravity and the curvature of spacetime.
In conclusion, while the equivalence principle may seem similar to Newton's third law on the surface, it is actually a distinct concept that has important implications in the study of gravity and general relativity. It is not simply a reiteration of Newton's third law, but rather a fundamental principle that helps us understand the nature of gravity and its effects on objects with different masses.
What is the equivalence principle?
The equivalence principle is a fundamental concept in physics that states that the effects of gravity are indistinguishable from the effects of acceleration. This means that an observer in a uniform gravitational field would not be able to tell the difference between standing on the surface of a planet or being in a spaceship that is accelerating at the same rate.
Who first proposed the equivalence principle?
The equivalence principle was first proposed by Albert Einstein in 1907 as part of his theory of general relativity. He believed that all objects, regardless of their mass or composition, would fall at the same rate in a uniform gravitational field.
Why is the equivalence principle important?
The equivalence principle is important because it helped Einstein develop his theory of general relativity, which is considered one of the most important theories in physics. It also helps us understand the relationship between gravity and acceleration, and can be used to make predictions about the behavior of objects in a gravitational field.
How is the equivalence principle tested?
The equivalence principle has been tested in various ways, including through experiments involving pendulums, free-fall objects, and gravitational redshift. One famous experiment that tested the equivalence principle was the Apollo 15 "feather and hammer" experiment, where an astronaut dropped a feather and a hammer on the moon and observed that they fell at the same rate.
Are there any exceptions to the equivalence principle?
While the equivalence principle is a fundamental concept, there are some situations where it does not hold true. For example, in extreme cases such as near a black hole, the effects of gravity and acceleration may not be equivalent. Additionally, the equivalence principle only applies in a vacuum and may not hold in the presence of air resistance or other external forces.
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