Displacement
the distance an object moves, measured in a straight line from the start point
Velocity
The speed of an object in a particular direction
The equation linking average velocity, displacement and time
Average velocity = displacement ÷ time
The equation linking average velocity, initial velocity and final velocity
Average velocity = (initial velocity + final velocity) ÷ 2
Acceleration
The rate of change of velocity or the amount that velocity changes per unit time
The equation linking acceleration, final velocity, initial velocity and time
Acceleration = (final velocity – initial velocity) ÷ time
Retardation
When an object is slowing down and its acceleration has a negative value