Motion
and Meters/Sec.
Velocity
Displacement in Time and Space
MPH
Machines, Mechanisms and
Motion are Intimately Related
Work = Force x Distance
Machines Produce Work by
Transforming Energy or Changing the
Direction or Distance Through Which a
Force Acts
Motion or Movement is a Change In
Position Called Displacement
Position A
10 ft.
Position B
Speed is the Rate of Displacement
Distance 10 ft
Speed 

 1 ft / sec
Time
10 sec
0
10
10 ft.
Seconds
Position A
Position B
Velocity is the Rate of Displacement
in a Specified Direction
0
Distance 10 ft
Speed 

 1 ft / sec
Time
10 sec
10
10 ft.
Position A
Seconds
Position B
Speed Equations
An object’s speed is a function of Displacement
(change in position) and Time (change in time
between positions)
d (d 2  d1 )
Speed 
t (t 2  t1 )
Speed Equations
A simple and useful version of the
Speed Equation Looks Like This
Distance
Speed 
Time
If You Want to Know the
Distance Traveled
Distance
Speed 
Time
You Can Rewrite the Equation Like
This
Distance  Speed  Time
Position-Time Graphs
1
2
3
4
5
6
7
8
9
Distance
20
40
60
80
100
120
140
160
180
160
Distance in Feet
Time
Distance (ft) Vs. Time (sec.)
200
120
80
40
0
1
2
3
4
5
6
7
Time in Seconds
8
Describes the Rate of Change in
Position of an Object Over Time
9
Position-Time Graph
Rise
Slope 
Run
Distance (ft) Vs. Time (sec.)
200
Distance in Feet
160
Distance
Speed 
Time
120
Rise
80
40
Run
0
1
2
3
4
5
6
7
Time in Seconds
8
The Slope is Equivalent to the
Average Speed
9
Position-Time Graph
Distance (ft) Vs. Time (sec.)
Distance 200
Speed 
Time
Δd  80ft
Δt  20sec.
Distance in Feet
160
120
Rise
80 ft.
80
40
80ft
Speed 
4sec.
0
1
2
Run 4
sec.
3
4
5
6
7
Time in Seconds
8
9
Speed = 20ft/sec.
How Fast is this Object Moving?
Position-Time Graph
160
Distance in Feet
The
constant
slope
indicates
that the
speed of the
object
remains
constant
Distance (ft) Vs. Time (sec.)
200
120
80
40
0
1
2
3
4
5
6
7
Time in Seconds
8
9
The Slope of this Line Remains
Constant Throughout the Graph
Position-Time Graph
Distance (ft) Vs. Time (sec.)
200
160
Distance in Feet
The Speed of
This Object
Changes
Over Time
The Object is
Accelerating
C
120
80
B
40
0
1
2
A
3
4
5
6
7
8
9
Time in Seconds
Speed @A = 5 ft/sec
Speed @B = 24 ft/sec
Speed @C = 50 ft/sec
Slope  Velocity
Average Speed Time Graphs
Speed in ft/second
50
40
30
20
10
0
1
2
3
4
5
6
7
Time in Seconds
8
9
Describes the speed of an object at specific times
and the total displacement but NOT the Direction
Study this graph and answer the questions
that follow
Average Speed Time Graphs
Speed in ft/second
50
40
30
20
10
0
1
2
3
4
5
6
7
Time in Seconds
8
9
How fast was this thing moving, 5 Seconds after it
began to move?
Hint: It began moving after 1 second
Average Speed Time Graphs
Speed in ft/second
50
40
30
20
10
0
1
2
3
4
5
6
7
Time in Seconds
8
9
Answer: 40 ft/second
Average Speed Time Graphs
Speed in ft/second
50
40
30
20
10
0
1
2
3
4
5
6
7
Time in Seconds
8
9
What was the total Displacement of this thing?
How far did the thing go during the whole trip?
Average Speed Time Graphs
Speed in ft/second
50
40
30
20
10
0
1
2
3
4
5
6
7
Time in Seconds
8
9
Answer: This Thing Traveled a total of 175 Feet
Distance = Speed x Time. Therefore the total
distance is the sum of the areas of each of the
5 rectangles! Try it….It works.
Another Difference Between
Speed and Velocity
Scalar Quantities
(One Number)
One Gallon
Distance
Speed (MPH)
Voltage
Speed is a Scalar
Quantity
Vector Quantities
(More Than One Number)
Machine Screw Specification
(tpi,length,diameter,head style)
Pant Sizes (Waist and Length)
Velocity (Speed and Direction)
Velocity is a Vector
Quantity
Vectors Graphically Describe
DIRECTION and MAGNITUDE
One
Foot/sec
+
One
Foot/sec
+
One
Foot/sec
=
3 Feet/sec
And You can Add and subtract Them!
Scaling Vectors
6 MPH
6 Inches
6 Centimeters
A Vector Describing a Velocity of 6 MPH is
Drawn With a Length of 6 Units
The Length of a Vector is Proportional to It’s
Magnitude
Vectors Can Describe Displacement
10 miles East
Point B
Point C
Total Displacement
12.2 miles North East of the
Starting Position
B2
7 miles
North
A2
C2
Point A
The magnitude of the Resultant
Vector is found using the
Pythagorean Theorem.
A2 + B2 = C2
Now…….Get Moving!
The End