13. Who’s Faster?
Speed = distance/time
180 meters
10 seconds = 180m 18 m/s
10 s
160 meters = 160m 20 m/s
8 seconds 8s
14. Speed or Velocity?
Speed –
the rate at which an object moves
how fast an object moves
15 m/s (meters per second)
Velocity –
an object’s speed in a specific direction
how fast AND
which way an object moves
5 m/s north
15. Speed or Velocity?
20 m/s - Speed
17 m/s east - Velocity
100 m/s up – Velocity
0.15 m/s - Speed
18. Warm-Up
Aug. 26,2011
Fill in the triangle with the formula for speed.
What is the velocity of a car that
traveled 252 miles East in 4 hours?
19. Speed = Distance/Time
D
S T
What is the velocity of a car that
traveled 252 miles E in 4 hours?
Distance 252 mi. = 63 mph E
Time 4 hr.
20. Acceleration
• Acceleration –
The rate at which velocity changes
A change in velocity
(Speed or Direction)
Examples:
Speeding up- A plane taking off
Slowing down- A car stopping at a red light
Changing direction – A car turning at a corner
23. Warm-Up
Aug. 29,2011
What two factors determine an
object’s speed?
Distance and Time
Practice Problem:
What is the velocity of a runner traveling
35 meters North in 7 seconds?
Speed = Distance = 35 m = 5 m/s
Time 7s