Acceleration

Front

Acceleration Noun

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[ak-sel-uh-rey-shuhn]

Back

Acceleration

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The rate at which the velocity of an object changes over time, involving a change in speed, direction, or both.

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Example: This image shows that acceleration is any change in velocity, which includes speeding up (runner), slowing down (skateboarder), or changing direction (bee).

Front

Velocity Noun

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[vuh-los-i-tee]

Back

Velocity

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A vector quantity that signifies the rate of change of position, indicating an object's speed and its direction of motion.

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Example: This car moves at a constant velocity, meaning its speed (20 m.p.h.) and its direction (left) do not change, resulting in zero acceleration.

Front

Vector Noun

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[vek-ter]

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Vector

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A physical quantity that is described by both a magnitude, which indicates its size, and a specific direction in space.

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Example: The arrow shows a push (a force), which is a vector because it has both a direction and a strength. This force causes the object to accelerate.

Front

Speed Noun

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[speed]

Back

Speed

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A scalar quantity that measures the rate at which an object covers distance, representing the magnitude component of velocity.

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Example: This image shows that speed is calculated by dividing the distance an object travels by the time it takes, a key concept for understanding motion.

Front

Deceleration Noun

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[dee-sel-uh-rey-shuhn]

Back

Deceleration

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A form of acceleration in which the speed of an object decreases over time, also referred to as negative acceleration.

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Example: This graph shows that when something brakes, its acceleration becomes a negative value over time. This negative acceleration is known as deceleration.

Front

Positive Acceleration Noun

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[poz-i-tiv ak-sel-uh-rey-shuhn]

Back

Positive Acceleration

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A form of acceleration where the velocity of an object increases in the direction of its motion over a period.

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Example: The top panel shows a runner speeding up, which is an example of positive acceleration, where the velocity of an object increases over time.

Front

Magnitude Noun

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[mag-ni-tood]

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Magnitude

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The size, amount, or numerical value of a physical quantity, considered separately from its associated direction.

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Example: This diagram shows a vector, like acceleration. The length of the arrow represents its magnitude (how large the acceleration is), while the arrowhead shows its direction.

Front

Centripetal Acceleration Noun

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[sen-trip-i-tl ak-sel-uh-rey-shuhn]

Back

Centripetal Acceleration

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The acceleration of an object moving in a uniform circular path, which is always directed towards the center of the circle.

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Example: An object moving in a circle has an acceleration (red arrow) that always points toward the center, constantly changing the direction of its velocity (blue arrow).