Acceleration is the rate of change of velocity, meaning how quickly an object's speed or direction changes over time. It can be positive if an object speeds up, or negative if it slows down or changes direction. Acceleration is calculated by taking the change in velocity and dividing by the time elapsed, using the formula a=(Vf - Vi)/t, where a is acceleration, Vf is final velocity, Vi is initial velocity, and t is time.

1. Acceleration

2. What is Acceleration? Speed is the rate of change of position. Acceleration is the rate of change of velocity. What does that mean it has? HINT

3. Acceleration Hints! Because velocity includes speed and direction of an object, acceleration can be a change in: How fast the object is moving What direction the object is moving Acceleration occurs when an objects changes its speed or direction, or both!

4. Speeding up or Slowing down? When a car speeds up, that is POSITIVE ACCELERATION! When a car slows down, that is NEGATIVE ACCELERATION or DECELERATION!

5. Acceleration Formula Acceleration = Change in Velocity/Time a=(Final Velocity-Initial Velocity)/Time a=(V f -V i )/t

6. Positive Acceleration A motorcycle starts at rest and accelerates to 80 m/s in 20 seconds a=(V f -V i )/t = (80 m/s – 0 m/s) / 20s a= 4 m/s 2

7. Positive Acceleration Graph

8. Negative Acceleration/Deceleration A skateboarder moves in a straight line at 3 m/s and comes to a stop in 2 s. a=(V f -V i )/t = (0 m/s – 3 m/s)/2s a= -1.5 m/s 2

9. Deceleration Graph