motion-a change in position. position- where an object is at a specific time (including direction) ...
TRANSCRIPT
SPEED AND ACCELERATION
Motion-a change in position. Position- where an object is at a
specific time (including direction) Ex. 7km North of Building A
Distance-interval of length – doesn’t include direction Ex. I walked 14km
An object at rest is a special case of motion in which there is not change in position
Speed vs. Velocity Speed-the distance an object travels
over a certain amount of time Speed is the rate of motion without
direction Rate-ratio between two different quantities
(distance/time) Units: m/s or km/hr Formula: Speed =d/t
(speed=distance/time) Constant speed-the speed does not change Instantaneous speed- the speed at a single
instant/moment of time
Speed vs. Velocity Velocity – change in position an object
travels over a certain amount of time Velocity includes a component of direction Units: Same as speed Formula: V= Direction can be shown by positive or
negative signs. Moving “forward” is positive Moving “backward” is negative
Direction can be shown by using compass directions Moving 35 mph north.
Position Graph
1 2 3 4 50
20
40
60
80
100
120
140
160
Position vs. Time
Time (hours)
Posit
ion
(m
iles)
How does graphing fit in?(It’s never going to go away!)
Position vs. Time graphs show where things are at different times which makes it easy to see how things have moved.
EX:
Moving Away Moving to Start Stopped (forward) (backward) (no motion)
P P P
TTT
How can the motion of an object be changed? Change how fast it is moving
Speed Up Slow Down
Change direction
*Note: Changing direction changesthe velocity but not the speed.
Changing Motion
Keep the graphing coming!!!
Distance vs. Time Graphs - show how long it takes an object to travel over a certain distance Show the motion of objects over a period of time Slope shows how speed changes at different places
T
D DD
TT
Increasing Decreasing Constant
Acceleration- the rate at which velocity changes
Formula: a= Example of units on acceleration:
m/s2 or m/s/s
Velocity Graph
1 2 3 4 5 60
1
2
3
4
5
6
Velocity vs. Time
Time (seconds)
Velo
cit
y (
m/s
)
• Velocity vs. Time Graphs- show how fast an object is traveling at a specific moment of time—Slope shows how an object is accelerating
TTT
V V V
Even more Graphing…….awwww yeah!!!
Positive
Acceleration
Negative
Acceleration
No Acceleration
(constant velocity)
Discussion
In a position vs. time graph, what does a negative slope mean?
In a velocity vs. time graph, what does a negative slope mean?