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Do Now!
| Date post: | 31-Dec-2015 |
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Do Now!
Today’s lesson
• Interpreting distance-time and speed-time graphs
A reminder
A reminder
Average speed = distance travelled
time taken
S tdx
Distance against time graphs
distance
time
Let’s go on the corridor!
Quietly and sensibly!
You’ll need a pencil and your
books
Distance/time graph
Distance /m
0 2 4 6 8 10 12 14 16
Time (slow)/s
Time (fast)/s
Distance/m 18 20 22 24 26 28 30 32
Time (slow/s
Time (fast)/s
No movement?
distance
time
No movement
distance
time
Constant speed?
distance
time
Constant speed
distance
time
Constant speed
distance
time
The gradient of this graph gives the speed
Constant speed
distance
time
How would the graph look
different for a faster constant
speed (walking to Physics)?
Constant speed
distance
time
fast
Constant speed
distance
time
fast
How would the graph look
different for a slower constant
speed (walking to French)?
Constant speed
distance
time
fast
slow
Constant speed
distance
time
fast
slow
The gradient of the graph gives
the speed
Constant speed
distance
time
Δy
Δx
Gradient = Δy/Δx
Let’s go on the corridor!
Quietly and sensibly!
You’ll need a pencil and your
books
Can you read what Mr Porter has written in your book and then
finish the questions you did last lesson?
Do now!
Distance/time graph - acceleration
Distance /m
0 2 4 6 8 10 12 14 16 18
Time/s
Distance/m 18 20 22 24 26 28 30 32
Time/s
Getting faster? (accelerating)
distance
time
Getting faster (accelerating)
distance
time
Examples
distance
time
A car accelerating from stop and then hitting a wall
distance
time
A car accelerating from stop and then hitting a wall
distance
time
Let’s try a simulation
Speed against time graphs
speed
time
Speed against time graphs
speed
time
No movement?
speed
time
No movement
speed
time
Constant speed?
speed
time
Constant speed
speed
time
Constant speed
speed
time
How would the graph look
different for a faster constant
speed?
Constant speed
speed
time
fast
Constant speed
speed
time
fast
How would the graph look
different for a slower constant
speed?
Constant speed
speed
time
fast
slow
Getting faster? (accelerating)
speed
time
Getting faster? (accelerating)
speed
time
Constant acceleration
Getting faster? (accelerating)
speed
time
The gradient of this graph gives the acceleration
Getting faster? (accelerating)
speed
time
a = v – u
t
(v= final speed, u = initial speed)
v
u
The gradient of this graph gives the acceleration
Getting faster? (accelerating)
speed
time
The area under the graph gives the distance travelled
Example:
speed
time
A dog falling from a tall building (no air resistance)
speed
time
A dog falling from a tall building (no air resistance)
speed
time
A dog falling from a tall building (no air resistance)
speed
time
Area = height of building
Be careful!
distance
time
speed
time
No movement
distance
time
speed
time
Constant speed
distance
time
speed
time
Area under graph = distance travelled
gradient = speed
Constant acceleration
distance
time
speed
time
Area under graph = distance travelled
Gradient = acceleration =
a = (v-u)/t
Reading – Pages 26 to 29
Now let’s try some questions!
Page 27 questions 2, 5, 6, 7.
Page 29 questions 1 & 2.
