1. Ch. 13 Gravitational Interactions

2. Gravitational Field

3. Does the gravitational field exist inside of a planet?????

4. Yes!!!

5. The force of Gravity, like other forces, causes acceleration! How does this relate to weight?

6. The force of Gravity, like other forces, causes acceleration! How does this relate to weight? How does this relate to weightlessness?

8. Support Force plays a factor in our concept of weight

9. Gravity at work on Earth! Ocean tides caused by differences in the gravitational pull of the moon on opposite sides of the Earth. – Pull is stronger when the moon is closer and weaker when it is further away.

10. Spring Tide

12. Black Holes Stars – Fusion reactions (H  He ) – Leading to increased mass and thus increased gravitational force! – When a star runs out of hydrogen, the star begins to cool and collapse, allowing a second fusion reaction to occur (He  C) – This will lead to another expansion of the star (Red Giant phase)

13. – When the helium is all used up, the Red Giant will collapse. (Black Dwarf) Black Holes: For stars 2-3 x bigger than the sun, once nuclear fusion stops, gravity takes over and it doesn’t stop! The star caves in on itself and the density inside is infinite. – Not even light can escape.

14. The biggest black hole in the universe weighs in with a mass of 18 billion Suns, and is about the size of an entire galaxy!

15. Mass of a black hole = mass of the star that it originated from – Gravitational field of the star and the black hole at distances greater than the original radius of the star are the same! F = Gm/d 2 – As distance approaches zero, Force of gravity is approaching infinity

16. Diagram of the gravitational field around a black hole. The center has the strongest force but at distances further away, the field is stable.

18. The End