Universal Gravitation

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Force Noun

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[fors]

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Force

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A push or a pull that can cause an object with mass to change its velocity, i.e., to accelerate.

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Example: This image shows a basketball being held and then released, falling downwards due to the force of gravity, demonstrating how this force causes acceleration.

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Gravity Noun

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[grav-i-tee]

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Gravity

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A natural phenomenon by which all things with mass or energy are brought toward one another, including planets and stars.

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Example: An apple falls from a tree branch, pulled downward by the force of Earth's gravity.

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Mass Noun

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[mas]

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Mass

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The intrinsic property of a body that measures its resistance to acceleration when a force is applied to it.

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Example: A balance scale shows the apple has more mass than the 1-gram weight, causing its side to tip down, illustrating mass as the amount of matter.

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Weight Noun

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[wayt]

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Weight

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The force exerted on an object by gravity, which depends on the object's mass and the local gravitational field.

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Example: This image displays six separate activities for comparing the mass of objects, incorrectly using the term 'weight' and failing to illustrate the scientific concept.

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Inertia Noun

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[in-ur-shuh]

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Inertia

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The property of matter by which it continues in its existing state of rest or uniform motion in a straight line.

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Example: When the moving car suddenly stops, the box on top continues to move forward because of its inertia, its resistance to a change in motion.

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Newton's First Law of Motion Noun

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[noo-tunz furst law uv moh-shun]

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Newton's First Law of Motion

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An object remains at rest or in uniform motion unless acted upon by a net external force.

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Example: This image displays a full lab worksheet designed to investigate Newton's First Law through a crash test dummy experiment, rather than providing a direct visual explanation.

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Gravitational Constant (G) Noun

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[grav-i-tey-shuh-nl kon-stuhnt]

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Gravitational Constant (G)

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An empirical physical constant used to calculate the gravitational force between two bodies, denoted by the letter G.

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Example: This diagram shows that two objects with mass (m1 and m2) pull on each other with an attractive gravitational force (F1 and F2).

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Newton's Law of Universal Gravitation Noun

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[noo-tunz law uv yoo-ni-vur-suhl grav-i-tey-shuhn]

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Newton's Law of Universal Gravitation

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A physical law stating that every particle attracts every other particle in the universe with a specific, calculable force.

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Example: This image shows that the force of gravity (F) exists between any two objects with mass (m1, m2), like the Earth and Moon, and this force depends on their masses and the distance (r) between them.

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Universal Gravitation Formula Noun

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[yoo-ni-vur-suhl grav-i-tey-shuhn for-myoo-luh]

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Universal Gravitation Formula

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The equation F = G(m1m2)/r², used to calculate the gravitational force between two objects based on their masses and distance.

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Example: This diagram shows that any two objects with mass, like the Earth and another celestial body, pull on each other with an equal and opposite gravitational force (F).

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Direct Proportionality Noun

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[di-rekt pro-por-shuh-nal-i-tee]

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Direct Proportionality

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A relationship between two variables where their ratio is a constant value, meaning they increase or decrease together.

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Example: This graph shows that as airplane size increases, the production cost increases at a constant rate, which is an example of direct proportionality.