Name: weightlessness and einstein’s equivalence
Uploaded: 2023-04-30T11:07:46.000Z
Duration: 1 min 18 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Physics

PH.9

PH.9.c

Principle of Equivalence

Prom kosmiczny krążący wokół Ziemi znajduje się w ruchu swobodnego spadania, ograniczony siłą grawitacji Ziemi. Jednak astronauta znajdujący się wewnątrz promu kosmicznego odczuwa stan nieważkości, jakby nie działała na niego żadna siła.
Załóżmy, że prom kosmiczny przyspiesza w górę z prędkością 9,8 m/s2; podłoga pomieszczenia promu kosmicznego przesunie się w górę w kierunku unoszącego się astronauty. Jednak astronaucie wydaje się, że przyspiesza w dół w kierunku podłogi promu kosmicznego z prędkością 9,8 m/s2.
Dla niego przyspieszenie powoduje przyciąganie w promie kosmicznym, podobne do grawitacji na powierzchni Ziemi. Siedząc w zamkniętym pomieszczeniu promu kosmicznego, astronauta nie jest w stanie odróżnić, czy znajduje się na Ziemi, czy przyspiesza w kosmosie.
Einstein stwierdził zatem, że nie ma różnicy między jednorodnym polem grawitacyjnym a jednostajnym przyspieszeniem przy braku grawitacji. Jest to znane jako zasada równoważności.
Doszedł do wniosku, że grawitacja nie jest siłą między dwiema masami, ale wyłania się z interakcji materii i przestrzeni.

zasada równoważności

Według Alberta Einsteina (1897-1955) swobodne spadanie i uczucie nieważkości są ze sobą nierozerwalnie powiązane. Gdyby ktoś spadał swobodnie pod wpływem grawitacji, na przykład nurkując z samolotu w kierunku Ziemi, czułby się całkowicie nieważki. Podobnie osoba zjeżdżająca windą może czuć się częściowo nieważka. Ogólnie rzecz biorąc, zakłada się, że obiekt w jednolitym polu grawitacyjnym i obiekt podlegający stałemu przyspieszaniu przy braku grawitacji znajdują się w tych samych warunkach eksperymentalnych (tj. żaden eksperyment nie jest w stanie rozróżnić tych dwóch scenariuszy). To stwierdzenie nazywa się zasadą równoważności.

Zasada odnosi się do podstawowego założenia prawa grawitacji Newtona: zakłada się, że masy określające siłę przyciągania grawitacyjnego między dwoma obiektami to te same masy, które określają ich reakcję na siły poprzez Newtona. prawa ruchu. Jednak te dwie masy, czasami nazywane masą grawitacyjną i masą bezwładnościową, mogą być w praktyce różne. Konsekwencje założenia, że ​​są one takie same, a więc wyniki połączenia prawa ciążenia Newtona z prawami ruchu Newtona, zgadzają się z eksperymentami. Innymi słowy, założenie okazuje się eksperymentalnie uzasadnione. Jednak przyczyna tej konsekwencji nie jest zrozumiała.

Zgodnie z zasadą równoważności nie jest to przypadek. Zasadniczo równomierne przyspieszenie i grawitacja są takie same.

Odnosząc równomierne przyspieszenie do grawitacji, Einstein zaproponował, że grawitacja nie jest siłą między dwoma obiektami. Zamiast tego jest to wpływ dwóch obiektów na otaczającą je czasoprzestrzeń, co z kolei determinuje ich dynamikę. Uczynił te idee matematycznymi w swojej ogólnej teorii względności w 1915 roku.

Ten tekst jest adaptacją <a href="https://openstax.org/books/university-physics-volume-1/pages/13-7-einsteins-theory-of- grawitacja">Openstax, University Physics, tom 1, sekcja 13.7: Teoria grawitacji Einsteina.</a>

Zasada równoważności

Według Alberta Einsteina (1897-1955) swobodne spadanie i uczucie nieważkości są ze sobą nierozerwalnie związane. Gdyby osoba znajdowała się w swobodnym spadaniu pod wpływem grawitacji, dla ...

Education

JoVE Core

Fizyka

Unit 1

Jednostka 1

Gravitation

Grawitacja

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

weightlessness and einstein’s equivalence

Weightlessness and Einstein’s equivalence principle are closely connected in gravity. A person in free fall under gravity, such as someone diving toward Earth from an airplane, would feel completely weightless. A person descending in a lift may feel partially weightless.

The principle of equivalence says that an object in a uniform gravitational field and an object accelerating at a constant rate with no gravity are under the same experimental conditions. In other words, no experiment can tell the two situations apart. This idea links gravity with uniform acceleration.

The principle also addresses a key assumption in Newton’s law of gravitation. It assumes that the mass that creates gravitational attraction is the same as the mass that responds to force in Newton’s laws of motion. These are sometimes called gravitational mass and inertial mass. They can be different in practice, but the results from combining Newton’s law of gravitation with Newton’s laws of motion still match experiments.

Einstein argued that this agreement is not a coincidence. He proposed that gravitation is not simply a force between two objects. Instead, it is an effect of those objects on the space-time around them, which then shapes their motion. He turned these ideas into mathematics in his general theory of relativity in 1915.

Weightlessness and Einstein’s Equivalence

gravitation

Newton’s Law Behind Planet Motion

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newton's law of gravitation

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gravitation between spherically symmetric masses

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acceleration due to gravity on other planets

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variation in acceleration due to gravity near the earth's surface

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circular orbits and critical velocity for satellites

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Orbital Speed and Period in Circular Paths

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Satellite Orbits and Energy in Space

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kepler's second law of planetary motion

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principle of equivalence

Weightlessness and Einstein’s equivalence principle are closely connected in gravity. A person in free fall under gravity, such as someone diving toward Earth from an airplane, would feel completely weightless. A person descending in a lift may feel partially weightless. The principle of equivalence says that an object in a uniform gravitational field and an object accelerating at a constant rate with no gravity are under the same experimental conditions. In other words, no experiment can tell...

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key terms and concepts

Learn how free fall, weightlessness, and constant acceleration connect in Einstein’s equivalence principle and why it led to general relativity.

Weightlessness and Einstein’s Equivalence | JoVE K12

physics

JoVE Core Physics introduces the theory and application of fundamental physics topics, including kinematics, dynamics, fluid mechanics, statics, waves, and acoustics, with concise and easy-to-understand animated videos. Additionally, the scientist-in-action videos demonstrate the application of related concepts in classical and original research experiments performed in today's laboratories worldwide.

Alabama Course of Study Science

9-12

Earth and Space Science

Earth's Place in the Universe

9-12.ESS.1.3

Florida Department of Education

High School

SC.912.E.5

SC.912.E.5.5

SC.912.E.5.10

Georgia Standards of Excellence

Astronomy

SAST4

SAST4.1

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PH.9.b

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PH.9.d

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The student will investigate and understand that extremely large and extremely small quantities are not necessarily described by the same laws as those studied in Newtonian physics. Topics, such as these listed, may be included. solid state physics;

PH.9.e

The student will investigate and understand that extremely large and extremely small quantities are not necessarily described by the same laws as those studied in Newtonian physics. Topics, such as these listed, may be included.

Weightlessness and Einstein’s Equivalence

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