1. CHAPTER 11 NOTES

2. Section 2: Acceleration
Acceleration-The rate at which velocity changes
An object accelerates when there is a change in speed, direction, or both!

3. The slope of a speed time graph would be acceleration
Calculating acceleration
Acceleration=final velocity-initial velocity Time
The slope of a speed time graph would be acceleration
Constant acceleration(steady change in velocity) =straight line

4. Velocity formula Velocity=distance/time V=d/t Put it in the triangle….

5. UNITS OF VELOCITY d= meters (m) t= seconds (s) v=meters/second (m/s
VELOCITY MUST ALWAYS INCLUDE A DIRECTION!!!
Use the same formula to calculate speed just don’t put a direction!!!

6. Convert days to seconds! 1 day=24 hours x 60 min x 60s
Metal stakes are sometimes placed in glaciers to help measure a glacier’s movement. For several days in 1936 Alaska’s Black Rapids glacier surged as swiftly as 89 meters per day. Find the velocity in m/s.
V=d/t
Convert days to seconds!
1 day=24 hours x 60 min x 60s
1 hour 1 min
V=d/t=89 m/86400 s
V=.001m/s down the valley

7. YOU TRY THESE!!
1.) Find the velocity in m/s of a swimmer who swims 110 m toward the shore in 72 s.
2.) Find the velocity in m/s of a baseball thrown 38 m from third base to first base in 1.7 s.
3.) Calculate the distance in meters of a cyclist would travel in 5 h with a velocity of 12 km/h to the southwest.

8. 1.) Find the velocity in m/s of a swimmer who swims 110 m toward the shore in 72 s.
V=d/t
V=110/72
V=1.5 m/s toward the shore

9. 2.)Find the velocity in m/s of a baseball thrown 38 m from third base to first base in 1.7 s.
V=d/t
V=38/1.7
V=22 m/s toward first base

10. 3.) Calculate the distance in meters of a cyclist would travel in 5 h with a velocity of 12 km/h to the southwest.
d=vt
d=12(5)
d=60 km
d=60 km (1000 m)
D=60000

11. ACCELERATION…
a=vf-vi/t
t=vf-vi/a
Vf=vi + at

12. a=vf-vi/t a=(14.7 m/s-0 m/s)÷1.5 s A=9.8 m/s2 down
A flower pot falls off a second story windowsill. The flowerpot starts from rest and hits the sidewalk 1.5 s later with a velocity of 14.7 m/s. Find the acceleration.
a=vf-vi/t
a=(14.7 m/s-0 m/s)÷1.5 s
A=9.8 m/s2 down

13. Let’s do another one…
Natalie accelerates her skateboard straight along a straight path from 0 m/s to 4 m/s in 2.5 s. Find her acceleration.
a=vf-vi/t
a=(4 m/s-0 m/s) ÷ 2.5
a=1.6 m/s2 along her path

14. TRY THESE ON YOUR PAPER!
1.) A turtle swimming in a straight line toward shore has a speed of .5 m/s. After 4 s it’s speed is .8 m/s, what is the turtle’s acceleration?
2.) Find the acceleration a northbound train that slows down from 12 m/s to 9.6 m/s in 8 s.
3.) Marisa’s car accelerates an average rate of 2.6 m/s2. Calculate how long it takes to speed up from 24.6 m/s to 26.8 m/s.

15. a=vf-vi/t a=(.8 m/s - .5 m/s)÷4 a=.075 m/s2 toward the shore
A turtle swimming in a straight line toward shore has a speed of .5 m/s. After 4 s it’s speed is .8 m/s, what is the turtle’s acceleration?
a=vf-vi/t
a=(.8 m/s - .5 m/s)÷4
a=.075 m/s2 toward the shore

16. 2.) Find the acceleration a northbound train that slows down from 12 m/s to 9.6 m/s in 8 s.
a=vf-vi/t
a=(9.6-12)÷8
a=-.3 m/s2 North

17. 3. ) Marisa’s car acclerates an average rate of 2. 6 m/s2
3.) Marisa’s car acclerates an average rate of 2.6 m/s2. Calculate how long it takes to speed up from 24.6 m/s to 26.8 m/s.
t=vf-vi/a
t=( ) ÷2.6
t=.84 s