distance
a scalar quantity that refers to “how much ground an object has covered” during its motion
distance does not include directional information
displacement
a vector quantity that refers to “how far out of place an object is”; it is the object’s net change in position
displacement includes a direction and magnitude.
∆x = x_2 - x_1
average velocity
displacement divided by time elapsed
average velocity is proportional to displacement and includes the same directional information (a vector quantity)
average velocity = ∆x/∆t
speed
a scalar quantity that refers to “how fast an object is moving”
speed does not include directional information, and can be thought of as the rate an object covers a distance
uniform motion
a time interval in which average velocity remains unchanged
in this special case, there is no difference between average and instantaneous measurements
instantaneous velocity
a vector quantity that implies the limit of the average velocity (∆x/∆t) as t approaches 0, or the derivative of an objects position with respect to time
Can speed ever be negative?
No, it is a magnitude
Can velocity ever be negative?
Yes, velocity is a vector
Acceleration
The rate at which velocity changes, a vector
Give an example of units for velocity
m/s
Given example for units of acceleration
m/s per s or m/s^2