
Distance
Total length of travel, from beginning to end. The distance is always positive.

Displacement
Displacement, Δx, is the change in position:
Δx= x_{f } x_{i
}Can be positive, negative, or zero.

Positive and Negative Displacement
The sign of the displacement indicates the direction of motion.
 Δx>0 motion to the right
 0<Δx motion to the left

Units (displacement & distance)
The SI unit of distance and displacement is the meter, m.

Average Speed
 Average speed is distance divided by elapsed time:
 average = distance/time
Never negative

Average Velocity
 Average velocity, v_{av}, is displacement divided by time:
 V_{av}=Δx/Δt=Δ_{f}x_{i}/t_{f}t_{i}
 Positive if motion is in the positive direction.
 Negative if motion is in the negative direction.

Units (velocity & speed)
The SI unit of speed and velocity is meters per second, m/s.

Instantaneous velocity
The velocity at an instant of time is the limit of the average velocity over shorter and shorter time intervals:
Can be positive, negative, zero, with the sign indicating the direction of motion.

Constant Velocity
When velocity is constant, the

Graphical interpretation of velocity
In a xversust plot, the average velocity is the slope of a line connecting two points.

Graphical interpretation
in a xversust plot, the instantaneous velocity at a given time is equal to the slope of a tangent line at that time.

Average acceleration
is the change in the velocity divided by the change in time.
 Its positive if Vf>Vi
 its negative if Vf<Vi

Instantaneous Accelaration
the limit of the average acceleration as the time interval goes to zero.

Constant acceleration
instantaneous acceleration is equal to the average acceleration.

decelaration
an object whose speed is decreasing is said yo be decelerating. whenever V and acceleration have opposite signs.

Graphical interpretation
in a vversust plot, the instantaneous acceleration is equal to the slope of the tangent line at a given time.

Units
The SI unit of acceleration is meters per second per second, or m/s^2

Acceleration due to gravity
varies slightly on the earths surface from place to place. Always a positive quantity.

