1. Acceleration
Chapter 2 Part 2

2. Changes of Velocity
As Velocity is a vector there are two things that can change:
Speed
Starting, Speeding up or down, stopping
Direction
Turning, circling etc. are changes of Velocity

3. Acceleration
Acceleration is the measure of the rate of change of Velocity It is always a vector. If acceleration and velocity are in the same direction… the object speeds up! If acceleration and velocity are in the opposite direction… the object slows down! If acceleration and velocity are perpendicular direction… the object turns without changing speed.

4. Straight Line Acceleration
Mathematically Acceleration in a straight line
(Also called tangential acceleration)
Is…
aavg = Δv/Δt
= (vf - vi) / (tf - ti)

5. Constant Linear Acceleration Formulae
Final Velocity: vf = vi + aΔt Displacement given velocities only: Δx= ½ ( vi + vf )Δt Displacement Formula: Δ x = viΔt + ½aΔt² or xf = xi + viΔt + ½aΔt² Final Velocity (with no time given): vf² = vi² + 2aΔx

6. “Surface Gravity” or “g”
Freefall
An object undergoing an acceleration due to gravity
toward the center of a planet is falling
Freefall is when a falling object accelerates due to
only gravity.
On Earth true freefall does not occur
Because air resistance acts against gravity
But for short falls it can be ignored.
Freefall acceleration near a planet (etc) is its:
“Surface Gravity” or “g”
On Earth g = -9.81m/s²
(in this book)