1. Observe the animation of the three cars below
Observe the animation of the three cars below. Which car or cars (red, green, and blue) are undergoing an acceleration?

2. DEFINITION
Acceleration is the rate at which velocity changes. In other words, knowing the acceleration of an object tells you how fast the velocity of the object is changing.
Acceleration is a vector quantity. " An object is accelerating if it is changing its velocity.  

3. A BODY OR OBJECT IS ACCELERATING WHEN BODY OR OBJECT:
 speeds up ( positive acceleration )
 slows down – this is called deceleration.
change direction - velocity changes if your direction changes (even if your speed stays the same).

4. HENCE, A BODY OR OBJECT IS ACCELERATING WHEN BODY OR OBJECT:
There is change is speed
There is change is direction
There is change is both speed & direction

5. You are accelerating if your velocity is changing, you are accelerating when you are changing direction - even if your speed stays the same.

6. ACCELERATION VS DECELERATION
Where do you have positive acceleration? Negative acceleration?
Straight Highway
Rough Road

7. ACCELERATION VS DELERATION?

8. ACCELERATION VS DELERATION?
Roller Coaster
Athlete approaching the finish line

9. ACCELERATION VS DELERATION?
A helicopter about to land
An PBA player aiming for a shot

10. HOW DO WE COMPUTE FOR ACCELERATION?
a = Vf - Vi
tf - ti
Where Vf is the final velocity
Vi is the initial velocity
tf is the final time
ti is the initial time
Common units: m/s2, km/hr2

11. PROBLEM 1
A school bus initially at rest moves with a final velocity of 60km/hr after 1 ½ hour. Find the acceleration of the bus.
Since bus is initially “at rest”
Given?
Vf = 60km/hr
Tf = 1.5 hr
Vi = 0 ti = 0
a = ?

12. PROBLEM 2
The initial velocity of a rolling wheelchair is 5m/s in 6 seconds. If the acceleration of the wheel is 2m/s2 then how fast is the wheelchair moving towards the ICU?

13. PROBLEM 2
Supposing blood in the aorta is accelerated by the action of the heart and it increases its velocity from zero to 0.38 m/s within 0.08 seconds then find the acceleration that took place.

14. PROBLEM 4
An Ambulance initially at rest achieved a final velocity of 90km/hr. How long will it take the ambulance to accelerate at 2km/hr2?
Given?
t = ?

15. Exercise on Acceleration
#1 1 & 2, #2  3 & 4 #3  5 & 6
An ambulance initially at rest moves with a final velocity of 70km/hr after 2 ½ hours. Find the acceleration of the ambulance.
2. The initial velocity of a rolling body is 2.5 m/s in 12 seconds. If the acceleration of the body is 2m/s2 then what is the final velocity of the rolling body?
3. A wheelchair initially at rest was achieved a final velocity of 1.5m/s after 2 minutes. Find the acceleration of the wheelchair.
4. The acceleration of a stretcher initially at rest is 0.9m/s2. If the final velocity is 1.8m/s then how long did it take it to achieve its final velocity?
5. Find the initial velocity of a car which accelerates at a rate of 0.55m/s2. The car achieved a final velocity of 20m/s in half an hour.
6. Supposing blood in the aorta is accelerated by the action of the heart and it increases its velocity from zero to a certain velocity within 0.06 seconds. Find the velocity if it was accelerated at 4m/s2.