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 with mass to change its velocity, i.e., to accelerate.

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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.

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Inertia Noun

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[in-ur-shuh]

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Inertia

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The natural resistance of any physical object to a change in its state of motion or rest.

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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.

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Mass Noun

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[mas]

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Mass

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A measure of the amount of matter in an object, which also quantifies its inertia and gravitational attraction.

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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 overall force acting on an object when all individual forces are combined as vectors, determining 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).

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Friction Noun

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[frik-shun]

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Friction

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A force that resists the relative motion or tendency of motion between two surfaces in contact with each other.

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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 that acts between all objects with mass, pulling them toward each other.

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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.

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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, calculated as its mass multiplied by the acceleration of gravity.

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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.

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Normal Force Noun

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[nor-muhl fors]

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Normal Force

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The support force exerted by a surface on an object, acting perpendicular to that surface to prevent penetration.

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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.

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Tension Noun

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[ten-shun]

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Tension

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The pulling force transmitted axially by means of a string, cable, chain, or similar 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-kwuh-lib-ree-uhm]

Back

Equilibrium

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A state in which the net force on an object is zero, resulting in no change in its motion.

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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.