1. Acceleration
Unit 9.1

2. velocity does not change
velocity changes

3. speed direction A change in velocity includes
_________ of an object changes
_____________ of an object changes
speed
direction

4. Dn = nf-ni
= 39-39
= 0 km/h
Dn = nf-ni
= -39-(-39)
= 0 km/h

5. Dn = nf-ni
= 39-0
= 39 km/h
increases
same direction
Dn = nf-ni
= -39-0
= -39 km/h
+ or -
Dn = nf-ni
= 0-60
= -60 km/h
decreases
opposite direction
Dn = nf-ni
= 0-(-60)
= 60 km/h
+ or -

6. Dn = nf-ni =
= -110 km/h

7. Dn = nf-ni = -5.4 m/s – (-1.2 m/s) = - 4.2 m/s Dn = nf-ni
Practice:
What is the change in velocity for a man that starts walking at 1.2 m/s south and speeds up to 5.4 m/s south?
What is the change in velocity for a ball thrown up into to the air with an initial velocity of 15 m/s up and the ball comes back down with a final velocity of 12 m/s down?
Dn = nf-ni
= -5.4 m/s – (-1.2 m/s)
= m/s
Dn = nf-ni
= -12 m/s – 15 m/s
= - 27 m/s

8. velocity
acceleration
Ddisplacement
Dvelocity
m/s2

9. increasing
constant
decreasing
positive
uniform
positive

10. positive negative negative positive slowing slowing positive negative
decelerating
slowing
slowing
decelerating
positive
negative
positive
negative
accelerating
speeding
accelerating
speeding