Motion Vocabulary

Motion

The act or process of changing position or place.

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PositionA place or location

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Frame of Reference

A system that uses coordinates to establish the precise position of objects in space and time. A group of objects that are not moving relative to each other.

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Relative motionThe continuous change of position of a body with respect to a second body or to a reference point that is fixed.

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Distance

The length of the path an object travels.

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Displacement

The distance and direction of an object’s final position from its initial position.

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Vector

A quantity that is specified by both a size and a direction.

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Speed

The distance an object travels per unit of time.

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Instantaneous speed

The speed of an object at a single instant of time.

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Average SpeedThe total distance an object travels divided by the total travel time.

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V = 12 m6 s

= 2 m/s

V = d

Δt

VelocityThe speed of an object and its direction of motion.

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V = ΔdΔt

V = 3 m6 s

= 0.5 m/s

Slope (m)The gradient or steepness of a line on a graph. It is the ratio of the change in y over the change in x.

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m = rise

run

m = y2 - y1

x2 - x1

m = 40 - 0100 - 0

m = 40100

m = 2.5

y = mx + bThe equation for a straight line written in “slope-intercept” form.

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AccelerationThe change in velocity divided by the time for the change to occur.

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Centripetal acceleration

The acceleration that occurs in circular motion.

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