10/29/2012
1 Satellites
Fast Moving Projectiles
Satellites
3 Satellites
Reflection
Mark your calendar for yesterday!
Our previous learning goal:
I understand the relationship altitude,
distance and projectile motion.
Using the scale, how do you think you are
doing with the concept?
2 Satellites
Projectile Motion and
Centripetal Force Review
Thrown
A projectile is any object that is _________
and continues in motion by its own
Inertia
_________.
4 Satellites
Gravity Review
Who was the first person who said that
gravity is universal – that is it works for
everything in the universe?
Newton!
Centripetal force is any force that causes
Circular
an object to follow a ______________
path.
1
10/29/2012
5 Satellites
7 Satellites
Newton and Gravity
Newton’s Mountain
One question that Newton thought about
was:
What did we see in the animation?
If the launch speed is great enough, the
launched cannonball becomes a
satellite!
Why does the Moon
continued to orbit
the Earth?
To help figure this out, he came up with a
model that we call Newton’s Mountain.
A satellite is a projectile or small body that
orbits around a larger body.
6 – Satellites
8 Satellites
Newton’s Mountain
Suppose you have
a cannon on top of
a very high
mountain and you
fire the cannonball
at a very high
speed.
Satellites
How does this work?
The Earth’s Curvature is 8000m/5m
In order to go into orbit around the Earth, a
projectile must reach a speed of 8 km/s or
18,000 miles/hr!
What will happen?
http://www.youtube.com/watch?v=8t2eyEDy7p4&feature=related
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=398
2
10/29/2012
9 Satellites
11 Satellites
Elliptical Orbits
Planetary Orbits
http://videos.howstuffworks.com/science-
channel/29276-100-greatest-discoverieselliptical-orbits-video.htm
The force due to gravity changes as the
satellite moves on its orbit
The velocity also changes as the satellite
moves
B
C
A
D
Where will the satellite be moving the fastest?
10 Satellites
12 Satellites
Elliptical Orbits
When a projectile is launched at a _________
greater than 8 km/s, it will _____________ a
circular path and its path will follow an ellipse
B
A
Escape Speed or
Velocity
What would happen if a
projectile was launched straight
up at 8 km/s?
C
D
Would it come straight back
down?
3
10/29/2012
13 Satellites
Escape Velocity
The Escape Velocity or Escape Speed
is the speed needed to “escape”
from the Earth’s gravity – 11.2 km/s
15 Satellites
Reflection
Mark your calendar!
Today’s learning goal:
I understand the relationship between
projectile motion and circular orbits.
Using the scale, how do you think you are
doing with the concept?
14 Satellites
Voyager 1
http://www.space.com/17205voyager-spacecraft.html
http://www.space.com/16259humankind-s-first-venture-intointerstellar-space-underwayvideo.html
4