Notes: Speed and Velocity

CW: Motion GraphsH: Pinewood Derby

Speed and Velocity

February 9, 2009

Objectives1. Define distance, time, speed, and

velocity2. Distinguish between and calculate

speed and velocity3. Explain constant speed and average

speed4. Read a distance time graph

Motion is measured by time and distance

Distance

the separation of two positions

Distance

Commonly measured in meters kilometers

Time

the period between two events

Time

Commonly measured in Seconds Minutes Hours

Speed

the measure of how fast an object moves as it changes its position

Speed

Commonly measured in Meters per minute

(m/m) Kilometers per hour

(km/h)

Speed = Distance Time

25 2030 1535 10 5 0

SpeedSpeedSpeedSpeed

Time = 0 secondsmeters

SpeedSpeedSpeedSpeed

Time = 5 secondsmeters

25 2030 1535 10 5 0

SpeedSpeedSpeedSpeed

Time = 10 secondsmeters

25 2030 1535 10 5 0

SpeedSpeedSpeedSpeed

Time = 15 secondsmeters

25 2030 1535 10 5 0

Constant Speed

speed that does not change

Constant Speed

0

10

20

30

40

50

60

Time (seconds)

Dis

tan

ce (

mete

rs)

Average Speed

the total distance traveled divided by the total time of travel

Average Speed

0

5

10

15

20

25

30

5 10 15 20 25 30 35 40 45 50 55

Time (s)

Velo

cit

y (

m/

s)

Speed & Velocity Speed & Velocity Speed & Velocity Speed & Velocity

How is speed different from velocity?

Velocity

describes both the speed and its direction

90 km/h = speed

90 km/h west = velocity