Aim: How can we explain Newton’s Universal Law of Gravitation? Do Now: Why does the moon orbit the...
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Transcript of Aim: How can we explain Newton’s Universal Law of Gravitation? Do Now: Why does the moon orbit the...
Aim: How can we explain Newton’s Universal Law of Gravitation?
Do Now:
Why does the moon orbit the Earth?
You will know by the end of the lesson
GravityGravityGravity is a universal law. Gravity is a universal law. Should behave the same where Should behave the same where
ever you are in the universe. ever you are in the universe. It's a force of attraction that It's a force of attraction that
exists between any two objects exists between any two objects that have mass. that have mass.
Gravity: similar to another Gravity: similar to another force of attractionforce of attraction
Love… awwLove… aww
The greater the The greater the mass, the more force mass, the more force of attraction of attraction
The closer the The closer the objects, the greater objects, the greater the force of attractionthe force of attraction
G is the Gravitational G is the Gravitational ConstantConstant
What does G equal and where can we find it?What does G equal and where can we find it?
Problems
What is the force of attraction between two football players (m1 = 80 kg and m2 = 100 kg) that are standing 1 m apart?
Fg = 5.4 x 10-7 N Not much attraction!
What is the force of attraction between the Earth and the Moon?
Fg = 2.0 x 1020 N
Now that’s a big attraction!
So why doesn’t the Moon fall to the Earth?
How is Fg proportional to m1 and m2?
They are directly proportional
If one goes up, the other goes up
What happens to the force if:
mass force double m1
triple m2
double m1 and m2
triple m1 and m2
½ m1
½ m1 and m2
2F
3F
4F
9F
½ F
¼ F
The trick:
•Start with easy numbers
•Manipulate
•Solve