1. Physical Science: Chapter 11
Acceleration

2. Physical Science: Chapter 11 Acceleration
When the velocity of an object changes the object is accelerating.

3. Physical Science: Chapter 11 Acceleration
Remember that velocity includes speed AND direction

4. Physical Science: Chapter 11 Acceleration
So if the speed of an object
increases
(speeds up)
it is
accelerating

5. Physical Science: Chapter 11 Acceleration
AND if the speed of an object
decreases
(slows down)
it is ALSO
“accelerating”

6. Physical Science: Chapter 11 Acceleration
AND if the motion of an
object changes
direction
it is ALSO
“accelerating”

7. Physical Science: Chapter 11 Acceleration
Acceleration by changing direction

8. Physical Science: Chapter 11 Acceleration
Acceleration = final velocity – initial velocity time (accelerating) a = vf –vi = m/s = m/s2 Δt s

9. Physical Science: Chapter 11 Acceleration
Δt = v f – vi a Δv = (a) x (Δt)

10. Physical Science: Chapter 11 Acceleration
Do Practice Problems p. 375 (1, 2, 3, 4)

11. Physical Science: Chapter 11 Acceleration
Do Practice Problems p. 377 (1, 2, 3, 4) 1). a = vf –vi = 4.0m/s-0.0m/s = 1.6m/s2 Δt 2.5s on path 2). a = vf –vi =0.8m/s-0.5m/s= 0.075m/s2 Δt 4.0s toward shore

12. Physical Science: Chapter 11 Acceleration
Do Practice Problems p. 377 (1, 2, 3, 4) 3). a = vf –vi = 9.6m/s-12m/s = -3.0m/s2 Δt 0.8s north (note: you could say 3.0 m/s2 south) 4). Δt = vf –vi = 26.8m/s-24.6m/s = 0.85s a 2.6 m/s2

13. Physical Science: Chapter 11 Acceleration
On a distance-time graph an
object with
increasing
acceleration
has a line
curving up.

14. Physical Science: Chapter 11 Acceleration
On a distance-time graph an
object with
negative
acceleration
has a line
going up, but
curving down.

15. Physical Science: Chapter 11 Acceleration
On a velocity-time graph, plot
Velocity
on the
y axis
time on the x axis

16. Physical Science: Chapter 11 Acceleration
On a velocity-time graph,
a constant
upward
sloping
line shows
constant positive acceleration

17. Physical Science: Chapter 11 Acceleration
On a velocity-time graph,
a line
curving
upward
shows
INCREASING positive acceleration

18. Physical Science: Chapter 11 Acceleration
On a velocity-time graph,
a line with
DECREASING
slope shows
positive acceleration

19. Physical Science: Chapter 11 Acceleration
On a velocity-time graph,
a “flat” line
(no slope)
shows NO
acceleration
(constant
velocity)

20. Physical Science: Chapter 11 Acceleration
On a velocity-time graph,
a constant downward sloping
line shows
negative
constant
acceleration

21. Physical Science: Chapter 11 Acceleration
On a velocity-time graph,
lines below 0 (zero) show
movement
“backwards”
(towards the
starting point)

22. Physical Science: Chapter 11 Acceleration
Velocity-time graph summary:

23. Physical Science: Chapter 11 Acceleration
Mini-Quiz #4
1). What is graphed on the y-axis
on a velocity-time graph?
2). What is graphed on the y-axis
of a distance-time graph?
3). What does a constant upward
sloping line on a distance-time graph
show?

24. Physical Science: Chapter 11 Acceleration
Mini-Quiz #4 In this graph what is happening: 4). between A & B? 5). Between B & C 6). Between C & D

25. Physical Science: Chapter 11 Acceleration
Mini-Quiz #4 In this graph what is happening: 7). In part A? 8). In part B? 9). In part C?

26. Physical Science: Chapter 11 Acceleration
Mini-Quiz #3 (Answers)
1). What is graphed on the y-axis on a velocity-time graph?
VELOCITY
2). What is graphed on the y-axis of a distance-time graph?
DISTANCE
3). What does a constant upward sloping line on a distance-
time graph show?
CONSTANT POSITIVE ACCELERATION

27. Physical Science: Chapter 11 Acceleration
Mini-Quiz #3
In this graph what is happening:
4). between A & B?
Constant positive
acceleration
5). Between B & C
velocity (speed)
6). Between C & D Constant negative acceleration

28. Physical Science: Chapter 11 Acceleration
Mini-Quiz #3
In this graph what is happening:
7). In part A?
Constant positive velocity
8). In part B?
Constant negative
acceleration
9). In part C?
Constant neg. acceleration, “BACKWARDS”.