1. Universal Gravitation
“Gravitation is universal.”

2. The Falling Apple
There must be a force causing the moon to travel in a circle!
What could it be?!
Hmm…Why does the apple always fall down and not up or sideways???

3. How far would each apple fall in 1 second?
g=0.0028m/s2
g=9.8m/s2
60R R

4. How far would each apple fall in 1 second?
4.9m
Gravity greatly reduces with distance!
1.4mm

5. The Falling Moon
} 1.4mm.
The moon falls in the sense that it falls beneath the straight line that it would follow if no force acted on it.

6. Tangential Velocity
Pull of Gravity

7. Newton’s Mountain

8. Maybe all objects have their own gravitational pulls…
Maybe all objects have their own gravitational pulls…?...The Earth and the Sun seem to…
Perhaps Earth’s gravity pulls on all things including an apple and the moon.

9. Why don’t the planets crash into the sun?

10. Newton’s Law of Universal Gravitation
Every object attracts every other object with a force that is directly proportional to the mass of each object and inversely proportional to the square of the distance between them.
Mass of one object
Mass of other object
Universal Gravitational Constant
Distance between CGs

11. Law of universal gravitation:
Does more mass mean more or less force?
More!
In direct proportion
Does more distance mean more or less force?
Less!
Way Less!
G=6.67x10-11 Nm2/kg2

12. Your Gravitational Pull…
On the Earth:
d=r=6.4x106m
myou=68kg
me=6x1024kg
On a Classmate:
d=1m
myou=68kg
mcm=68kg

13. Why do we not feel ourselves gravitate toward massive buildings?
Gravity is the weakest of the fundamental forces!
We really only feel gravity when objects are planet sized!

14. How far apart must 2 objects be in order to for there to be no gravitational force between them?
Betelgeuse is 600 light-years away!
Can a student leave the classroom by halving their distance to the door?

15. Plot this in your calculator
Inverse Square Law
Plot this in your calculator

16. Imagine a journey to the center of the Earth
Imagine a journey to the center of the Earth! What would happen if you entered a well that passed through the entire Earth?!

17. Why is the Earth round? The Sun?

18. Picture this…