1. Acceleration 2.2

2. Objectives Perform acceleration calculations.
Explain how positive and negative acceleration affect motion.
CLE Investigate the relationships among speed, position, time, velocity, and acceleration.

3. Acceleration * change in speed or direction
A. Acceleration - rate of change in velocity
* change in speed or direction

4. Acceleration
1. Positive acceleration - speed is increasing. “speeding up”
2. Negative acceleration - speed is decreasing. “slowing down”

5. Negative Acceleration (Deceleration)
Decreasing or (-) velocity
Slowing down

6. Acceleration 3. When an object changes speed
or direction, it is accelerating.

7. Acceleration 2
Changing Direction
The speed of the carousel is constant. Why is acceleration changing?

8. Acceleration, Speed and Velocity2
Acceleration, Speed and Velocity
The speed of the horses in this carousel is constant, but the horses are accelerating because their direction is changing constantly.
** Acceleration occurs when an object changes its speed, its direction, or both.

9. Roller coasters
B. Amusement park acceleration - roller coasters - remember
1. Changes in speed cause acceleration.
2. Changes in direction cause acceleration

10. Acceleration
Rate at which the velocity of a moving object changes
Final Velocity – Starting Velocity Time
Change in Velocity ÷ Time

11. t a C. Acceleration Acceleration the rate of change of velocity
vf - vi t
C. Acceleration
Acceleration
the rate of change of velocity
change in speed or direction
a: acceleration
vf: final velocity
vi: initial (starting) velocity
t: time

12. Equation
a = ( vf - vi ) ÷ t
v = ( vf - vi )
= change in
= delta -

13. Calculating Acceleration
C. Calculating acceleration
1. Acceleration = change in velocity / time
2. Change in velocity = final velocity - initial velocity
3. Unit for acceleration - meters per second squared (m/s2)

14. To find change in velocity, subtract the starting velocity (vi ) from the final velocity (vf)
acceleration = change in velocity
time
a = vf - vi / time

15. Calculating Acceleration2
Calculating Acceleration
Using this expression for the change in velocity, the acceleration can be calculated from the following equation:

16. t a D. Calculations a = (vf - vi) ÷ t t = 3 s
A roller coaster starts down a hill at 10 m/s. Three seconds later, its speed is 32 m/s. What is the roller coaster’s acceleration?
GIVEN:
vi = 10 m/s
t = 3 s
vf = 32 m/s
a = ?
WORK:
a = (vf - vi) ÷ t
a = (32m/s - 10m/s) ÷ (3s)
a = 22 m/s ÷ 3 s
a = 7.3 m/s2 a
vf - vi t

17. http://www. biologycorner

18. Graphing Acceleration
The slope of a line on a graph showing speed and time.
Changes in slope show change in acceleration.
Page 49-50

20. E. Graphing Motion slope = +ve = speeds up -ve = slows down
Speed-Time Graph
acceleration
+ve = speeds up
-ve = slows down
slope =
straight line =
flat line =
constant accel.
no accel. (constant velocity)

21. E. Graphing Motion Speed-Time Graph
Specify the time period when the object was...
slowing down
5 to 10 seconds
speeding up
0 to 3 seconds
moving at a constant speed
3 to 5 seconds
not moving
0 & 10 seconds

22. CLE 3202.3.1 Investigate the relationships among speed, position, time, velocity, and acceleration.
Objective: Perform calculations involving time, distance, velocity, and acceleration.

24. Acceleration is the rate of change of __________.
Section Check 2
Question 1
Acceleration is the rate of change of __________.

25. Section Check 2
Answer
The correct answer is velocity. Acceleration occurs when an object changes its speed, direction, or both.

26. Which is NOT a form of acceleration?
Section Check 2
Question 2
Which is NOT a form of acceleration?
A. maintaining a constant speed and direction
B. speeding up
C. slowing down
D. turning

27. Section Check 2
Answer
The answer is A. Any change of speed or direction results in acceleration.

28. Section Check 2
Question 3
What is the acceleration of a hockey player who is skating at 10 m/s and comes to a complete stop in 2 s?
A. 5 m/s2
B. -5 m/s2
C. 20 m/s2
D m/s2

29. Objective: Explain how positive and negative acceleration affect motion.
Section Check 2
Answer
The answer is B. Calculate acceleration by subtracting initial velocity (10 m/s) from final velocity (0), then dividing by the time interval (2s).
(0 m/s – 10 m/s) = – 5 m/s2 2s

30. http://glencoe. mcgraw-hill

31. CLE 3202.3.1 Investigate the relationships among speed, position, time, velocity, and acceleration.
Objective: Perform calculations involving time, distance, velocity, and acceleration.
Objective: Explain how positive and negative acceleration affect motion.

32. Objectives
Perform calculations involving time, distance, velocity, and acceleration.
Explain how positive and negative acceleration affect motion.
CLE Investigate the relationships among speed, position, time, velocity, and acceleration.