5. How fast would a bowling ball have to be moving for it to clear the gap in the elevated alley and continue moving on the other side?

6. A body in free fall falls 4.9m in the first second of fall.
16 ft
1 sec

7. 8 km
4.9 m

8. 8 km/sec. In fact, you could remove the whole alley!
How fast would a bowling ball have to be moving for it to clear the gap in the elevated alley and continue moving on the other side?
8 km/sec. In fact, you could remove the whole alley!

9. Ball launched horizontally from a cannon with no gravity

10. Add in gravity…

11. Now with a slightly larger velocity…

12. V = 8 km/s

13. V > 8 km/s

15. Would a cannon ball fired upward at 8 km/s go into Earth orbit?
No! It would simply act as a projectile and crash back into the Earth at 8 km/s. To circle the Earth it must have a tangential speed of 8 km/s

16. Law of Universal Gravitation
Every body in the universe attracts every other body with a mutual force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
Where: G = 6.67x10-11 N m2/kg2
The Universal Gravitation Constant

20. He is obviously attracted to her
He is obviously attracted to her. But, how much force of attraction is there?
Assume: His mass = 80. kg
Her mass = 52 kg.

21. He is obviously attracted to her
He is obviously attracted to her. But, how much force of attraction is there?
0.75m
Assume: His mass = 80 kg
Her mass = 52 kg.
= 4.9x10-7N

22. Example: A satellite is orbit around the Earth makes one complete revolution every 3 days. At what altitude is the orbit? (Mass of Earth = 6.0 E 24 kg, Radius of Earth = 6.4 E 6 m)

23. The altitude of the distance above the surface of the Earth.
Altitude = 8.80x x106
Altitude = 8.16x107m

24. How do the Tides work?

25. But what about the bulge on
the other side?

26. What we already know: The water under the
moon is closer to the moon then the center
of the Earth is. So the moon’s gravity pulls
harder on the water and the water “heaps
up” under the moon.

27. The New Part: The center of the Earth
is closer to the moon then the water on
the OPPOSITE side of the Earth. The
moon pulls the Earth away from the water,
and it appears to “heap up” too.

28. Spring Tides
Neap Tides