1. November 10, 2015
Bell Work
Why does a piece of crumpled paper land before a flat piece of paper on earth but not on the moon?

2. Learning Target You will be able to explain Universal Gravitation.
You will be able to describe how the Law affects earth and the objects on it.

3. Agenda Watch Eureka Video-Gravity Cartoon Physics Notes
Time to work on Pkt.

4. Q: So what does the Universal Law of Gravitation tell us?
Force of gravity is DIRECTLY proportional to the product of the masses of the 2 objects.
If we increase both masses, the force will increase.

5. Q: So what does the Universal Law of Gravitation tell us?
If we double mass of object 1 and double mass of object 2, the force of gravity between them will……
QUADRUPLE! (2 X 2 = 4)
If we triple the mass of object 1 and double the mass of object 2, the force of gravity between them will…….
increase by a factor of 6 (2 x 3 = 6)

6. Q: So what does the Universal Law of Gravitation tell us?
If we double the mass of one object and cut the mass of the other in half, the force of gravity between them will ………
remain the same (2 x 1/2 = 1)

7. Q: So what does the Universal Law of Gravitation tell us?
At the same time, the force of gravity between 2 objects is INVERSELY proportional to the distance squared
As we increase the distance, the force will decrease.

8. Q: So what does the Universal Law of Gravitation tell us?
If we double the distance between two objects (increase by a factor of 2), then the force of gravity between them is……
decreased by a factor of 4 (22 = 4).
-(The force is ¼ of the original!)

9. Q: So what does the Universal Law of Gravitation tell us?
If we triple the distance between two objects (increase by a factor of 3), then the force of gravity between them is……
decreased by a factor of 9 (32 = 9).
-(The force is 1/9 of the original!)

10. Q: Why does this happen?
The relationship between gravity and distance is that of the inverse square law.
Force is inversely related to the square of the distance

12. Q: Why does this happen?
So the further something gets from the center of the earth, the less gravitational force.
When you go all the way to the moon, you don’t have a lot of gravitational force acting on you, so your weight decreases (because weight is a direct measure of the gravitational force!)

14. Q: So how can you find out how much gravitational force there is between two objects?
We must use the universal gravitational constant – G.
It is termed a "universal constant" because it is thought to be the same at all places and all times.

15. What would the units be? Lets look…
Q: So how can you find out how much gravitational force there is between two objects?
G = 6.67 x N*m2/kg2
What would the units be? Lets look… x =

16. Q: What’s the deal with tides?
Gravity of both the moon and sun pull on the Earth to make the tides occur.
The moon’s gravity has a larger influence on tides.
The gravitational pull of the sun is greater (it’s more massive), but it is too far away to have a big influence.

18. Q: What’s the deal with tides?
As the moon passes over the ocean, there is a swell in the sea level. As the moon passes to the other side of the planet, the swell occurs there.
High tide on one side of the Earth means low tide on the other side.
Imagine sloshing water around in a container or in a bathtub.

19. Q: What’s the deal with tides?
Tides are not affected by the phase of the moon.
No matter the phase, the moon is the same distance away and has the same mass, so the pull of gravity stays the same.

20. *BRING BOOKS MONDAY Homework Complete Gravity HW Pkt –Due Thursday
Collect the Univeral Gravitation Simulation Lab. You must read this before class tomorrow.
We are in the Computer Lab tomorrow- Room 215
Gravity Test Monday
*BRING BOOKS MONDAY