Motion 1-1, 1-2 Key Terms
Theory of Plate Tectonics
The theory that pieces of Earth's outer layer are in constant motion
Instantaneous speed
the speed of an object at one instant of time
reference point
A place or object used for comparison to determine if an object is in motion
International system of Units
A system of measurement based on multiples of ten and on established measures of mass, length, and time.
plates
Large pieces of earths crust that move due to convection currents.
Velocity
Speed in a given direction
Meter
The basic SI unit of length.
speed
The distance an object travels per unit of time
average speed
The overall rate of speed at which an object moves; calculated by dividing the total distance an object travels by the total time.
slope
The steepness of a line on a graph
motion
When one object's distance from another is changing.
