Transcript Document

GRAVITY
Warm Up:
1. What are your ideas about gravity?
◦What is it?
◦What causes it?
◦What changes it?
◦How does it affect things?
2. What variables do you think affect gravitational
force?
Objective/ SWABAT:
Predict how the gravitational force between two
bodies would differ for bodies of different
masses or different distances apart.
WA St Standard PS1F
Explore what affects gravity
using Gravity Force Lab applet
1. Go to:
http://phet.colorado.edu/en/simulation/gravity-force-lab
2. Click the
to run the program.
3. COPY and Answer questions 1-6 in your journal
http://www.universetoday.com/34824/force-of-gravity/
Homework
Read
Take DETAILED
Notes
GRAVITY
Warm Up:
1. When considering gravity, where is the distance between the objects
measured from?
2. What is an
independent (manipulated)
and dependent (responding)
variable?
Hint: DRY MIX
Collect and graph data
Today you will create three graphs relating
independent variables to the gravitational forces
experienced by the objects.
These graphs will be turned in.
GRAVITY
Warm Up:
DRY MIX
What is that?
What does it help us recall?
How does it apply to graphing?
Graph data
Today you will create three graphs relating
independent variables to the gravitational forces
experienced by the objects.
Tomorrow these graphs are due!
If you complete these graphs. Please begin on the
questions 1-9, due Friday.
GRAVITY
Warm Up:
Show me your amazing graphs
1. Get out the graphs you created
2. Check to make sure each has labeled axes, title,
units, data table, trend line and YOUR NAME
3. What does this graph mean?
Whiteboard and Interpret
In 6.42 minutes…or less to prepare, then we will
present the whiteboards.
1. Graph the shape of your assigned independent
variables to the gravitational forces experienced
by the objects.
2. Write 2 statements that describe the
relationship of the variables graphed
3. Present your board
What does this shape tell us about the
relationship of gravity and distance?
GRAVITY
Discuss with your group which two variables
you believe affect gravity the most.
Review of Gravity
Today in class…
Reading assessment #3
Questions 1-9,
due stapled to graphs Monday
Objective/SWBAT:
Explain how weight of
an object can change while
its mass remains constant.
WA St Standard PS1F
Can you calculate the attractive force you and
the Earth experience because of each other?
Careful with units!
•Radius of the Earth is 6,371 km. (needs to be in meters)
•Mass of the Earth is
5.974 x 10^24 kg.
•1 kg = 2.2 lb
•N= (kg m) /s2
School House Rocks GRAVITY
http://www.universetoday.com/34824/force-of-gravity/
White board
your portion
Whole class
Take DETAILED
Notes
Today in class…
Questions 1-9,
due stapled to graphs Monday- hey
that’s today!
Calculate the attractive force you and the
Earth experience because of each other.
Careful with units!
•Radius of the Earth is 6,371 km. (needs to be in meters)
•Mass of the Earth is
5.974 x 10^24 kg.
•1 kg = 2.2 lb
•N= (kg m) /s2
School House Rocks GRAVITY
GRAVITY
Warm Up:
What is acceleration?
What causes an object to accelerate?
How might acceleration relate to gravity?
Acceleration
1. Acceleration is a change in direction or speed
of an object.
2. Acceleration is caused by a net force acting
on an object.
Does this data show acceleration?
What is causing the velocity to change?
What is the shape
of a velocity: time
graph for this
data?
Position is changing at a
NON-CONSTANT rate,
Velocity is changing
Velocity is changing at a
CONSTANT rate,
acceleration is constant
Rate of acceleration is
CONSTANT9.8 m/s2 on Earth
Confused?
Fg
and
g
Fg is the mutual force created by the 2 objects interacting.
g is the acceleration due to gravity.
Paper, book, and a white board
GRAVITY
Entry task: Bowling ball and a Soccer Ball
(on a half sheet with your name):
Write a claim of which ball will hit the ground first.
Then…Explain which will hit first a bowling ball or a soccer ball using
force diagrams.
1.
Draw 2 force diagrams.
2.
One that shows the forces acting on a bowling ball as it falls.
3.
The other showing the forces acting on a soccer ball as it falls.
Bowling ball or soccer ball?
Aristotle vs Galileo
Brainiac Video
https://www.youtube.com/watch?v=AYz_K3mwq6A
What falls faster?
A feather or a bowling ball?
https://www.youtube.com/watch?v=E43-CfukEgs
Falling Objects misconceptions
https://www.youtube.com/watch?v=_mCC-68LyZM
Exit ticket
Explain which will hit first a bowling ball or a soccer ball using
force diagrams.
1. Draw 2 force diagrams.
2. One that shows the forces acting on a bowling ball as it
falls.
3. The other showing the forces acting on a soccer ball as it
falls.
4. Add a statement about what might change with terminal
velocity
GRAVITY
Free Fall- the affect of acceleration and
inertia
http://www.telegraph.co.uk/news/science/space/9849206/Felix-Baumgartner-fell-faster-thanwe-thought-supersonic-skydiver-hit-Mach-1.25.html
http://arstechnica.com/science/2012/10/skydiver-breaks-speed-of-sound-after-jumping-fromedge-of-space/
Terminal Velocity
https://www.youtube.com/watch?v=9imImfmt2BE
GRAVITY
Warm Up:
Make sure you have the value of “g” written in your
notes.
Notes can be used on the Quest tomorrow.
Now that you know the acceleration due to
the force gravity is 9.81 m/s2… I bet you are
wondering where that number comes from,
right?
Astronauts Feather and Hammer
https://www.youtube.com/watch?v=-4_rceVPVSY
See how “g” applies
?
?
Do you weigh
the same on
Earth and the
moon?
Why is that?
Mass and weight are different- I’m going on a
moon diet
Putting it all together…
1. What 3 variables affect gravitational force?
2. What is Newton’s Law of Gravitation?
3. What is Newton’s second law?
g = 9.81 m/s/s
You may calculate the gravitational
force on the astronaut on the Earth given the
Following:
Radius of the Earth 6,371,000 m
Mass of the Earth 5.974 x 10^24 kg
Putting it all together… Why is it that the
weight of the astronaut changes?
What 2 variables affect gravitational force?
What is Newton’s Law of Gravitation?
What is Newton’s second law?
g = 9.81 m/s/s
You may calculate
the gravitational
force on the
astronaut on the moon given the
Following.
Radius of the Earth 6,371,000 m
Radius of the Moon 1,737,100 m
Mass of the Earth 5.974 x 10^24 kg
Mass of the Moon 7.347 x 10^22 kg
Write it on you whiteboard. Show your math.
g=?
Calculate weight (force due to gravity) in the following problems by using the equation:
weight = mass x free-fall acceleration
w=mg
g (on Earth) = 9.8 m/s2
(1) ALWAYS write the equation
(2) plug in the numbers and units,
(3) give the answer with the correct units.
1. A physical science text book has a mass of 2.2 kg
a) What is the weight on the Earth?
b) What is the weight on Mars (g = 3.7 m/s2)
2. If the textbook weighs 19.6 newtons on Venus, What is the strength of gravity
on Venus?
3. Of all the planets in our solar system, Jupiter has the greatest gravitational
strength. If a 0.5 kg pair of running shoes would weigh 11.55 newtons on
Jupiter, what is the strength of gravity there?
4. If he same pair of shoes weighs 0.3 newtons on Pluto, what is the strength of
gravity on Pluto?
5. What does the pair of shoes weigh on Earth?
Quest Review
GRAVITY
http://www.history.com/shows/theuniverse/videos/the-universe-gravity
Senate Constitutional Convention:
The Universe:
Gravity Episode
Please answer the
Guided Questions
GRAVITY