ch 2 representing motion p 30 - weebly
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Physics Ch 2.notebook2.1 Picturing Motion
motion involves place and time
motion diagram: shows a series of images with the position of a moving object at equal time intervals
Physics Ch 2.notebook
Aug 282:59 PM
2.2 When and Where?
Coordinate System : defines the zero point of the variable you are studying and the direction in which the values of the variable increase.
think of an xaxis....
0 origin
Aug 282:59 PM
you can indicate how far the object in motion is from the origin by drawing an arrow from the origin to the point the object has reached
0 meters
5 10 15 20 25 30 35 40
this arrow represents the object's POSITION : the separation between an object and the origin
This can be positive or negative to indicate direction from the origin
the length of the arrow indicates the object's DISTANCE from the origin how far an object is from the origin
This does not indicate direction
Physics Ch 2.notebook
0 meters
5 10 15 20 25 30 35510152025
0 meters
5 10 15 20 25 30 35510152025
position?
distance?
You CAN have a negative position, but not a negative distance
+15 m 15 m
only have magnitude
ex: position
ex: distance
to add scalars
to add vectors
like always.....there is no direction to worry about, so just do the math
4.0 m + 5.0 m = 9.0 m
you have to consider direction
4.0 m east + 5.0 m east = ?
you can add them graphically by using the vector arrows, tail to tip
0 1 2 3 4 5 6 7 8 9 10 11 12
the RESULTANT: the sum of the other vectors
always points from the tail of the first vector to the tip of the last
eastwest
Aug 282:59 PM
0 1 2 3 4 5 6 7 8 9 10 11 12
6.0 m east + 3.0 m west = ?
eastwest
What is the final position?
What is the distance travelled?
3 m East 9 m
Physics Ch 2.notebook
so t = time interval = difference between two times
t = tf ti final time
initial time
A runner starts at the origin. He passes a tree two seconds later. He finishes the race in 15 seconds.
What is the time interval between the tree and the finish line?
What is the time interval between the tree and the start line?
time = scalar
= df did
0 1 2 3 4 5 6 7 8 9 10 11 12
6.0 m east + 3.0 m west = ?
eastwest
final position
initial position
Draw the resultant (remember, tail of 1st to tip of last)
what is the final position? (tip of resultant)
what is the distance travelled?
what is the final displacement?
Which of these quantities are vectors? They need a direction.
Which is a scalar? No direction included.
Physics Ch 2.notebook
Aug 282:59 PM
= df did We can also add/subtract vectors NONgraphically, using the formula
What is the displacement when an object moves 9m east?
0 1 2 3 4 5 6 7 8 9 10 11 12west
so d = 9m 0m = 9m east
= df did
Aug 282:59 PM
What is the displacement when an object moves from 5m east to 9m east?
0 1 2 3 4 5 6 7 8 9 10 11 12west
so d = 9m 5m = 4m east
= df did
We can define di as something other than the origin
Physics Ch 2.notebook
What is the displacement if an object moves 6m west?
we defined to the right (+) as east and to the left () as west
= df did = 6m 0m = 6md
the negative indicates direction
NOT that it is less than zero magnitude
so from 0m to 6m west, the object was displaced 6m west
1234567
Aug 282:59 PM
0 1 2 3 4 5 6 7 8 9 10 11 12 west east
What is the displacement if an object moves from 6m east to 3m east?
we defined to the right (+) as east and to the left () as west
= df did = 3m 6m = 3md
so from 6m east to 3 m east, the object was displaced 3 m west
Physics Ch 2.notebook
Aug 282:59 PM
0 1 2 3 4 5 6 7 8 9 10 11 12 west
6.0 m east + 3.0 m west = ?
east
what is the displacement? = df did
Aug 282:59 PM
P 38 Position Time Graphs
motion diagram: simple display of an object's location at various times
. . . . . . . . . 1s 2s 6s0s
t=0 ti tf
Aug 282:59 PM
The same information can also be expressed in a positiontime graph
time on horizontal (x) axis
position on vertical (y) axis
0 5 10 15 20 25 305 meters
1 2 3 4 5 6 time0
motion diagram
this is the same information in a table
0.0 0.0 1.0 5.0 2.0 10.0 3.0 15.0 4.0 20.0 5.0 25.0 6.0 30.0
Time t (s) Position d (m)
Aug 282:59 PM
5
10
15
20
25
30
notice:
this is NOT the path the object has taken.
the graph line is sloped, but the runner's path was flat
this is a pictoral representation of the table data
we can use this graph to estimate different times and/or positions
Physics Ch 2.notebook
0 (High Street)
time (s)
distance (m)
50
20
Aug 282:59 PM
Since the object is in motion, it is only at a position for an instant.
We define an instant of time as 0 seconds.
d of an object in motion = instantaneous position
Motion of multiple objects:
the objects have the same position when their lines intersect
this does NOT mean they will necessarily collide
0 504010 20 30
Aug 282:59 PM
Aug 282:59 PM
2.4 How Fast? Position and time can be used to describe the rate of motion of an object
Velocity If two moving objects are travelling at different rates,
1) in a fixed time span, d will be greater for the faster moving object
2) if they both cover the same distance, the time interval will be smaller for the faster moving object
Physics Ch 2.notebook
In 1.0 second, how far did the red jogger get?
In the same time interval, how far did the blue jogger get?
The jogger with the greater distance travelled in the one second time interval has a line with a steeper slope.
slope = rise/run = y / x
= (df di) / (tf ti)
slope of a position time graph = average velocity label = m/s indicates it is telling you how many meters the object moved in one second
Aug 282:59 PM
the sign (+/) indicates direction
position
Be sure to label your answer.
This IS the average velocity.
Speed is the absolute value of velocity because it is a scalar quantity no direction is included.
What is the speed of this object?
Physics Ch 2.notebook
What is its average speed?
Aug 282:59 PM
Instantaneous Velocity: speed and direction of an object at a particular instant
average velocity
instantaneous velocity
time t (min)
what is m?
what is b?
time t (s)
y = mx + b becomes:
motion involves place and time
motion diagram: shows a series of images with the position of a moving object at equal time intervals
Physics Ch 2.notebook
Aug 282:59 PM
2.2 When and Where?
Coordinate System : defines the zero point of the variable you are studying and the direction in which the values of the variable increase.
think of an xaxis....
0 origin
Aug 282:59 PM
you can indicate how far the object in motion is from the origin by drawing an arrow from the origin to the point the object has reached
0 meters
5 10 15 20 25 30 35 40
this arrow represents the object's POSITION : the separation between an object and the origin
This can be positive or negative to indicate direction from the origin
the length of the arrow indicates the object's DISTANCE from the origin how far an object is from the origin
This does not indicate direction
Physics Ch 2.notebook
0 meters
5 10 15 20 25 30 35510152025
0 meters
5 10 15 20 25 30 35510152025
position?
distance?
You CAN have a negative position, but not a negative distance
+15 m 15 m
only have magnitude
ex: position
ex: distance
to add scalars
to add vectors
like always.....there is no direction to worry about, so just do the math
4.0 m + 5.0 m = 9.0 m
you have to consider direction
4.0 m east + 5.0 m east = ?
you can add them graphically by using the vector arrows, tail to tip
0 1 2 3 4 5 6 7 8 9 10 11 12
the RESULTANT: the sum of the other vectors
always points from the tail of the first vector to the tip of the last
eastwest
Aug 282:59 PM
0 1 2 3 4 5 6 7 8 9 10 11 12
6.0 m east + 3.0 m west = ?
eastwest
What is the final position?
What is the distance travelled?
3 m East 9 m
Physics Ch 2.notebook
so t = time interval = difference between two times
t = tf ti final time
initial time
A runner starts at the origin. He passes a tree two seconds later. He finishes the race in 15 seconds.
What is the time interval between the tree and the finish line?
What is the time interval between the tree and the start line?
time = scalar
= df did
0 1 2 3 4 5 6 7 8 9 10 11 12
6.0 m east + 3.0 m west = ?
eastwest
final position
initial position
Draw the resultant (remember, tail of 1st to tip of last)
what is the final position? (tip of resultant)
what is the distance travelled?
what is the final displacement?
Which of these quantities are vectors? They need a direction.
Which is a scalar? No direction included.
Physics Ch 2.notebook
Aug 282:59 PM
= df did We can also add/subtract vectors NONgraphically, using the formula
What is the displacement when an object moves 9m east?
0 1 2 3 4 5 6 7 8 9 10 11 12west
so d = 9m 0m = 9m east
= df did
Aug 282:59 PM
What is the displacement when an object moves from 5m east to 9m east?
0 1 2 3 4 5 6 7 8 9 10 11 12west
so d = 9m 5m = 4m east
= df did
We can define di as something other than the origin
Physics Ch 2.notebook
What is the displacement if an object moves 6m west?
we defined to the right (+) as east and to the left () as west
= df did = 6m 0m = 6md
the negative indicates direction
NOT that it is less than zero magnitude
so from 0m to 6m west, the object was displaced 6m west
1234567
Aug 282:59 PM
0 1 2 3 4 5 6 7 8 9 10 11 12 west east
What is the displacement if an object moves from 6m east to 3m east?
we defined to the right (+) as east and to the left () as west
= df did = 3m 6m = 3md
so from 6m east to 3 m east, the object was displaced 3 m west
Physics Ch 2.notebook
Aug 282:59 PM
0 1 2 3 4 5 6 7 8 9 10 11 12 west
6.0 m east + 3.0 m west = ?
east
what is the displacement? = df did
Aug 282:59 PM
P 38 Position Time Graphs
motion diagram: simple display of an object's location at various times
. . . . . . . . . 1s 2s 6s0s
t=0 ti tf
Aug 282:59 PM
The same information can also be expressed in a positiontime graph
time on horizontal (x) axis
position on vertical (y) axis
0 5 10 15 20 25 305 meters
1 2 3 4 5 6 time0
motion diagram
this is the same information in a table
0.0 0.0 1.0 5.0 2.0 10.0 3.0 15.0 4.0 20.0 5.0 25.0 6.0 30.0
Time t (s) Position d (m)
Aug 282:59 PM
5
10
15
20
25
30
notice:
this is NOT the path the object has taken.
the graph line is sloped, but the runner's path was flat
this is a pictoral representation of the table data
we can use this graph to estimate different times and/or positions
Physics Ch 2.notebook
0 (High Street)
time (s)
distance (m)
50
20
Aug 282:59 PM
Since the object is in motion, it is only at a position for an instant.
We define an instant of time as 0 seconds.
d of an object in motion = instantaneous position
Motion of multiple objects:
the objects have the same position when their lines intersect
this does NOT mean they will necessarily collide
0 504010 20 30
Aug 282:59 PM
Aug 282:59 PM
2.4 How Fast? Position and time can be used to describe the rate of motion of an object
Velocity If two moving objects are travelling at different rates,
1) in a fixed time span, d will be greater for the faster moving object
2) if they both cover the same distance, the time interval will be smaller for the faster moving object
Physics Ch 2.notebook
In 1.0 second, how far did the red jogger get?
In the same time interval, how far did the blue jogger get?
The jogger with the greater distance travelled in the one second time interval has a line with a steeper slope.
slope = rise/run = y / x
= (df di) / (tf ti)
slope of a position time graph = average velocity label = m/s indicates it is telling you how many meters the object moved in one second
Aug 282:59 PM
the sign (+/) indicates direction
position
Be sure to label your answer.
This IS the average velocity.
Speed is the absolute value of velocity because it is a scalar quantity no direction is included.
What is the speed of this object?
Physics Ch 2.notebook
What is its average speed?
Aug 282:59 PM
Instantaneous Velocity: speed and direction of an object at a particular instant
average velocity
instantaneous velocity
time t (min)
what is m?
what is b?
time t (s)
y = mx + b becomes: