 Vocabulary  Acceleration: The rate at which velocity changes  Constant acceleration: A steady change in velocity  Announcements:

Science 8 th Grade

 S8P3. Students will investigate relationship between force, mass, and the motion of objects.  a. Determine the relationship between velocity and acceleration. (DOK 2)

 It is a rate!  Let’s try this one more time…what is a rate?  Right…right…  What is changing?  Velocity  Standard unit: meters per second squared (m/s 2 )

 Speed!  Positive acceleration  Positive change in speed  Increase speed  Negative acceleration  Negative change in speed  Decrease speed

 Speed and direction  Yes, changing at the same time.

 From the vocabulary, we know it is steady change in velocity  Essentially, a constant rate change in velocity  Or…velocity is changing the same amount each second  /watch?v=BGfPU_g yqm8 /watch?v=BGfPU_g yqm8

 a = v f – v i t  a – acceleration  v f – final velocity  v i – initial velocity  t – time  Units?  Try some problems.

1. A car traveling at 10 m/s starts to decelerate steadily. It comes to a complete stop in 20 seconds. 2. An airplane travels down the runway for 4.0 seconds with an acceleration of 9.0 m/s 2.

 Demonstrated on a speed vs. time graph  The slope demonstrates acceleration  Or…increasing or decreasing slope of distance-time graph

 Explain how acceleration is considered a rate?  It is a vector too… what does that mean?  What kind of graph shows acceleration?