reference point
a point used to describe the position of an object
velocity
describes the speed and direction of motion
acceleration
the rate at which velocity changes over time am object does this if it's speed, direction or both change
rolling friction
rounded objects roll over a flat surface
static friction
objects slide past each other
friction
unbalanced force that acts against an object's motion
speed
the distance traveled divided by the time interval during which the motion occurred (tells how fast)
instantaneous speed
the speed at a given time or interval
constant speed
an object covers equal distance in equal amounts of time
force
any action that changes the state of motion of an an object