# 1.2 – Speed measures how fast position changes

```Section 1.2
Speed measures how fast
position changes.
MRS. LEOS
 How far is Wet ‘n Wild?
 What
are different ways to
describe how far somewhere is?
EXPLORE: (page 16)
How can you measure speed?
 PURPOSE: To introduce the relationship
among speed, distance, and time.
 How can you measure speed?
 Read through procedure on pg 16
 Answer What do you think Questions in ISN.
Position can change at different
rates.
 Speed
is a measure of how fast something
moves or the distance it moves, in a given
amount of time.
 The
greater the speed an object has,
the faster it changed position.
 Look at the picture on p 17
 What does each group of numbers in a box
represent?
 How can you tell which cyclist is pedaling
faster?
 How far will each rider travel in 5 seconds?
Calculating Speed
Distance
and time measurements
 The formula for speed (average)
Speed
= Distance/Time
S = d/t
 Let’s practice!
 A wheelchair racer completes a 100-meter
course in 20 seconds. What is his speed?
 A dog runs 200 m in 25 s on the beach.
What is his speed? Raise your hand
 If a remote-control car travels 100 m in
50 s, what is its speed?
 If two runners cover the same distance in
different amounts of time, how do their
speeds compare?
Average Speed
 Instantaneous speed (moment-to moment speed) is
hard to measure, therefore it is easier to calculate
Distance-Time Graphs
 Shows how speed relates to distance and time
 TIME is on the x- axis (horizontal)
 DISTANCE is on the y-axis (vertical)
 IN YOUR OWN WORDS SUMMARIZE bullets 1,2,3
Calculating Speed from a Graph
 How fast is the zebra walking during the first
20 seconds?
 Practice Math problems
 How do the distances change over each 10
second time interval?
Velocity includes speed and
direction
 Velocity= speed in a specific direction
 Example: walking east at a speed of three meters
per second
 Vector: a quantity that has both size AND direction
(velocity)
 Two objects can have the same speed but different
velocities (same speed, different directions)
 On page 26 (left side of notebook),