Name: free-fall acceleration on earth
Uploaded: 2023-09-22T11:49:39.000Z
Duration: 55 s
Channel: JoVE

Prenons l’exemple d’une dame qui pousse un chariot à bagages pendant qu’elle se déplace. La force externe exercée par elle accélère le chariot dans la direction de la force appliquée.
Si elle pousse avec une force plus grande, le chariot se déplacera plus rapidement. Pour arrêter le chariot, elle doit appliquer une force externe dans la direction opposée à son mouvement.
Si elle place plus de bagages sur le chariot, la même force produit une accélération plus faible dans la direction de la force externe nette.
En les compilant, nous obtenons la deuxième loi du mouvement de Newton, qui stipule qu'un objet accélère proportionnellement et dans la direction de la force externe nette et inversement à sa masse.
Ou encore, la force externe nette agissant sur un objet est le produit de sa masse et de son accélération. Tous les objets en accélération suivent la deuxième loi de Newton.

accélération due à la gravité sur terre

La deuxième loi de Newton est étroitement liée à sa première loi du mouvement. Elle donne mathématiquement la relation de cause à effet entre la force et les changements de mouvement. La deuxième loi de Newton est quantitative et est utilisée de manière extensive pour calculer ce qui se passe dans des situations impliquant une force. Toutes les forces externes agissant sur un système s'ajoutent pour produire une force nette Fnet. Une force nette externe plus grande produit une accélération plus grande. Cette accélération est directement proportionnelle à la force nette externe agissant sur un système et dans la même direction.

De plus, il semble également raisonnable que l'accélération soit inversement proportionnelle à la masse d'un système. En d'autres termes, plus la masse (l'inertie) est grande, plus petite est l'accélération produite par une force donnée. Des expériences ont montré que l'accélération est exactement inversement proportionnelle à la masse, tout comme elle est directement proportionnelle à la force nette externe. Il a été trouvé que l'accélération d'un objet dépend uniquement de la force nette externe et de la masse de l'objet. En combinant les deux proportionnalités, on obtient la deuxième loi de Newton, qui affirme : l'accélération d'un système est directement proportionnelle à la force nette externe agissant sur le système, et est inversement proportionnelle à sa masse.

La deuxième loi décrit comment un corps répond mécaniquement à son environnement. L'influence de l'environnement est la force nette, la réponse du corps est l'accélération, et la force de la réponse est inversement proportionnelle à la masse.

Newton a également exposé sa deuxième loi en termes de quantité de mouvement : le taux instantané de variation de la quantité de mouvement d'un corps est égal à la force nette agissant sur le corps.

Ce texte est adapté de <a href="https://openstax.org/books/university-physics-volume-1/pages/5-3-newtons-second-law">Openstax, University Physics Volume 1, Section 5.3: Newton's Second Law.</a>

Accélération due à la gravité sur Terre

La deuxième loi de Newton est étroitement liée à sa première loi du mouvement. Il donne mathématiquement la relation de cause à effet entre la force et les changements...

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Acceleration due to Gravity on Earth

free-fall acceleration on earth

Free-fall acceleration on Earth describes how fast an object speeds up when gravity is the only force acting on it. Near Earth’s surface, this acceleration is nearly constant for many everyday situations.

Gravity pulls objects toward Earth and gives them downward acceleration. This motion is often written as g, and it helps explain why falling objects gain speed as they move downward.

The value of g is commonly used in physics to predict the motion of objects dropped or released near the ground. It is an important idea for understanding motion on Earth and for solving basic mechanics problems.

Free-Fall Acceleration on Earth

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position and displacement

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position and displacement vectors

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acceleration due to gravity on earth

Free-fall acceleration on Earth describes how fast an object speeds up when gravity is the only force acting on it. Near Earth’s surface, this acceleration is nearly constant for many everyday situations. Gravity pulls objects toward Earth and gives them downward acceleration. This motion is often written as g, and it helps explain why falling objects gain speed as they move downward. The value of g is commonly used in physics to predict the motion of objects dropped or released near the...

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key terms and concepts

Learn how free-fall acceleration near Earth works, why gravity makes falling objects speed up, and how g is used in basic physics problems.

Free-Fall Acceleration on Earth | JoVE K12

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Free-Fall Acceleration on Earth

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