1. J. C. Booth Middle School Physical Science (8A) Coach Dave Edinger
Acceleration
J. C. Booth Middle School
Physical Science (8A)
Coach Dave Edinger

6. 1. What is acceleration?
Our definition: the rate at which velocity changes.
A way of describing how fast something speeds up or slows down

7. 2. What kind of motion does acceleration refer to?
Increasing speed
Decreasing speed
Changing direction
or any change in velocity (speed and direction)

26. How can a car be accelerating if its speed is constant at 65 km/h?
It can accelerate by changing direction!

27. 3. How do you calculate acceleration?
You must calculate the change in velocity per unit of time.
Formula:

28. 4. How is it expressed? Usually meters per second per second
m/s/s or m/s2

29. Example: Calculate the plane’s acceleration after 5 seconds.
Initial velocity =
Final velocity =
Time =

30. = 40 m/s – 0 m/s
5 s
= 8 m/s2

31. 6. Example: a car slows down from 60 m/s to 10 m/s in 10 seconds
6. Example: a car slows down from 60 m/s to 10 m/s in 10 seconds. What is its acceleration?
a = 10 m/s – 60 m/s
10 s
a = -50 m/s
10s
a = -5 m/s/s or -5 m/s2

34. 7. What is negative acceleration?
Slowing down or decelerating

35. 8. How can you graph acceleration?
Speed versus time graph!
X-axis = time
Y-axis = speed
Accelerating!

36. How would the slope of the graph change if the cyclist were accelerating at a greater rate?
The slope would be steeper!
What about a lesser rate?
The slope would be less steep

37. 9. How can you interpret graphs of speed versus time?
Speed is increasing
Positive acceleration

38. Speed
Speed is decreasing
Negative acceleration
Time (s)
Speed
Speed remains the same
Constant speed!
Time (s)

39. Or by a distance versus time graph

41. Xcelerator at Knott’s accelerates the passengers from 0 m/s to 38 m/s in 2.3 seconds. What is the acceleration?

42. 10. What is the difference between a linear and nonlinear graph?
Linear = straight line
Nonlinear = not a straight line