1. Acceleration

2. Acceleration Acceleration is the rate of change in velocity. Acceleration can be a change in speed or direction.

3. Directions of Acceleration Changing direction is also considered a change in acceleration This is because acceleration is defined as the change in velocity over time, and velocity is dependent on direction.

4. Directions of Acceleration When acceleration is in the same direction as velocity, speed increases VelocityAcceleration When acceleration is in a different direction than velocity, speed decreases VelocityAcceleration

5. Calculating Acceleration To calculate acceleration, the change in velocity is divided by the time interval. Change in velocity =  v = v f – v i Average Acceleration = a =(v f – v i )/t The unit for acceleration is m/s 2

6. Example 1 A car goes from 0 m/s to 30 m/s in 10 seconds. What is the average acceleration? v f = 30 m/s, v i =0 m/s, t= 10 seconds a = v f – v i /t = (10m/s – 0m/s)/10 s = 3m/s 2

7. Example 2 A roller coaster starts down a hill with a hill with an average velcity of 11 m/s. It reaches the bottom of the hill in 3 s and has a velocity of 32 m/s. What is the average acceleration? v f = 32 m/s, v i =11 m/s, t= 3 seconds a = v f – v i /t = (32m/s – 11m/s)/3s = 7m/s 2

8. Graphing Acceleration A velocity/time graph displays the velocity of an object over time. The y-axis is the velocity of an object The x-axis is the time The slope of the line is the acceleration