Acceleration

1. Acceleration
Integrated Physics and Chemistry

2. Acceleration
 Group up with one other student and
discuss the following:
What does acceleration mean?
What are three examples of acceleration?
 Write your responses in your notes.

3. Acceleration
 Acceleration – change in velocity over
time.
 a = ΔV/t = Final velocity – Initial Velocity
Time
 Acceleration is a “rate”
 Units m/s2

4. Acceleration
 When an object is increasing in velocity
over time it is said to be accelerating.
(positive acceleration)
 When an object is decreasing in velocity
over time it is said to be decelerating.
(negative acceleration)
 If an object is moving at constant velocity
it is said to be moving with zero
acceleration

5. Three Ways to “Accelerate”
 Speed Up
 Slow Down
 Change Direction

6. Constant Acceleration
 Acceleration that does not change over
time.

7. Instantaneous Acceleration
 The acceleration of an object at any point
in time.

8. Acceleration due to Gravity
 Do all objects fall at the same rate?
 Discus with partner….yes or no???
 https://youtu.be/aRhkQTQxm4w
 The acceleration of an object in free fall
due to the earth’s gravity is 9.80m/s2.

9. Practice Problems
1. An Indy-500 car’s velocity increases from 4.0
m/s to 36 m/s over a 4.0 second period. What
is the acceleration?
a = v final – v initial / t
a = 36 m/s – 4.0 m/s = 32m/s = 8.0 m/s²
4.0 s 4.0 s

10. Practice Problems
2. The same car slows from 36 m/s to 15 m/s
over 3 seconds. What is its average
acceleration over this time interval?
a = v final – v initial / t final – t initial
a = 15 m/s – 36 m/s = -21m/s = -7 m/s²
3.0 s - 0 s 3.0 s
“decelerating”

11. Practice Problems
 A bus is moving at 25 m/s. The driver
steps on the brakes, and the bus stops in
3.0 seconds.
 What is the acceleration of the bus while
braking?

12. Practice Problems
a = v final – v initial / t
a = 0 m/s – 25 m/s = -25 m/s = -8.3 m/s²
3.0 s 3.0 s
“decelerating”

13. Acceleration due to Gravity
 The acceleration of an object in free fall
due to the earth’s gravity is 9.8m/s2.
 What is the final velocity of a book that
falls from a shelf in 3.2secs?