Newton's First Law

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Force Noun

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[fors]

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Force

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Any push or pull that causes an object to change its motion, with the SI unit being the Newton (N).

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Example: This diagram shows how a force from a compressed spring causes a ball at rest to move, demonstrating that a force is a push or pull that can change an object's motion.

Front

Inertia Noun

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[in-ur-shuh]

Back

Inertia

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An object's natural resistance to any change in its state of motion, whether it is at rest or moving.

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Example: When the car suddenly stops, the box continues to move forward because of its inertia, its tendency to resist a change in motion.

Front

Mass Noun

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[mas]

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Mass

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The quantitative measure of an object's inertia, representing the amount of matter contained within it.

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Example: This image shows a balance scale comparing a rock and a feather, visually demonstrating that the rock has more mass than the feather.

Front

Net Force Noun

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[net fors]

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Net Force

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The vector sum of all the individual forces acting on a single object, which determines its acceleration.

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Example: This image shows two forces (F1 and F2) pulling a box in the same direction, which add together to create a larger total or net force (FR).

Front

Friction Noun

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[frik-shun]

Back

Friction

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A force that opposes the relative motion or the tendency of such motion between two surfaces in contact.

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Example: This diagram shows that friction is a force that opposes the push (applied force) on an object, caused by the roughness of surfaces rubbing together.

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Gravity Noun

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[grav-i-tee]

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Gravity

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The universal force of attraction acting between all matter, pulling objects with mass toward one another.

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Example: An apple, initially at rest on a branch, is pulled downward by the force of gravity, causing it to accelerate towards the ground.

Front

Weight Noun

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[wayt]

Back

Weight

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The force exerted on an object due to gravity, calculated as the product of its mass and gravitational acceleration.

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Example: Weight is the force of gravity (g) pulling on an object's mass (m), calculated by W=mg. This force is what a scale measures.

Front

Normal Force Noun

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[nor-muhl fors]

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Normal Force

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The support force exerted upon an object that is in contact with another stable object, acting perpendicular to the surface.

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Example: A book on a table experiences a downward pull from gravity (weight) and an equal upward push from the table, called the normal force.

Front

Tension Noun

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[ten-shun]

Back

Tension

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The pulling force transmitted axially by a string, cable, chain, or other one-dimensional continuous object.

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Example: This image shows tension as the pulling force in a rope during a tug-of-war, where the equal and opposite forces result in a balanced system.

Front

Equilibrium Noun

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[ee-kwi-lib-ree-uhm]

Back

Equilibrium

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The state of a body in which the net force acting upon it is zero, resulting in no acceleration.

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Example: This seesaw is in equilibrium because the forces are balanced. The downward weights of the children are opposed by the upward force from the pivot, resulting in no net force and no movement.