1. https://www.youtube.com/watch?v=ttZCKAMpcAo VSV 2015

2. Gravity: A force of attraction Make things move….faster, slower and change direction…also gravity makes them change shape… READING: Gravity: A force of Attraction (574 – 579) Answer the 10 questions from page 579 in your notebook VSV 2015

3. Sir Isaac Newton VSV 2015

4. Why do objects fall toward the Earth, and what keeps the planets moving in the sky? The law of universal gravitation describes the relationships between gravitational force, mass and distance. https://www.youtube.com/watch ?v=jwPc0kK9VHU VSV 2015

5. The Law of Universal Gravitation All objects in the universe attract each other through gravitational force VSV 2015

6. PART 1 PART 2 VSV 2015

7. Distance, Mass, Fg VSV 2015

8. All matter has mass All matter is affected by gravity All objects experience an attraction toward all other objects Because of gravity you are being pulled right now! Why don’t you notice objects moving toward each other?. Mass is too small. Remember VSV 2015

9. Weightless? (NASA pictures) VSV 2015

10. GRAVITY is a force of attraction between objects due to their masses. WEIGHT IS A MEASURE OF GRAVITATIONAL FORCE VSV 2015

11. So when gravity pulls something towards the Earth, we can call this force WEIGHT (W) W = mg So when gravity pulls something towards the Earth, we can call this force WEIGHT (W) W = mg VSV 2015

12. So when gravity pulls something towards the Earth, we can call this force WEIGHT (W) W = mg So when gravity pulls something towards the Earth, we can call this force WEIGHT (W) W = mg N = Kg. m S 2 VSV 2015

13. The force of gravity you experience due to the Earth (w) is proportional to your own mass (m). w = mg The force of gravity you experience due to the Earth (w) is proportional to your own mass (m). w = mg 'g' is the gravitational field strength  the force with which gravity pulls each kilogram of mass. 'g' is the gravitational field strength  the force with which gravity pulls each kilogram of mass. What is “g”? w = mg w = (100 kg) (9.83 N/Kg) w = mg w = (100 kg) (9.83 N/Kg) W = mg W = (100 kg) (9.83 N/Kg) W = 100 x 9.83 N W = 983 N W = mg W = (100 kg) (9.83 N/Kg) W = 100 x 9.83 N W = 983 N VSV 2015

14. apparently weightless (pictures or animation only –not a demonstration) VSV 2015

15. On the Moon – Apollo 15 http://www.youtube.com/watch?v=MJyUDpm9Kvk A heavy geological hammer and a falcon feather were dropped from the same height. They hit the lunar surface at the same time. astronaut David Scott NASA pictures VSV 2015

16. Very heavy boots- Why? Answers? No gravity on the Moon Weightless on the Moon To stop them floating away They weigh very much less than on Earth To stop huge bounces The Moon’s gravity is very much less than the Earth’s gravity VSV 2015

17. GRAVITY Things fall Things have weight Things stay in place No Gravity Would an apple fall? Would things stay on earth? What would happen? What? Why? How? VSV 2015

19. “If Wile E. Coyote and a boulder fall off a cliff at the same time, which do you think will hit the ground first?” VSV 2015

21. two objects dropped at the same time GALILEO GALILEI https://www.youtube.com/watch?v=_mCC-68LyZM https://www.youtube.com/watch?v=NMM8vx9vDiE VSV 2015

22. GRAVITY AND ACCELERATION Objects fall to the ground at the same rate because the acceleration due to gravity is the same for all objects. VSV 2015

23. ACCELERATION DUE TO GRAVITY It means that every second that an object falls, the object’s downward velocity increases by 9,8 m/s² All objects accelerate toward Earth at a rate of 9,8 m/s² VSV 2015

24. Velocity of a falling object: Δ V = g x t ΔV = final velocity – starting velocity (m/s) g = acceleration due to gravity (9,8 m/s²) t = time the object takes to fall in seconds SOLVE MATH FOCUS EXERCISES (PAGE 591 IN YOUR COPIES ) VSV 2015

26. Net Force = 0 N A stops Constant velocity X X Only gravity is pulling the object down VSV 2015

27. AN ELEPHANT AND A FEATHER Suppose that an elephant and a feather are dropped off a very tall building from the same height at the same time. Which object - the elephant or the feather - will hit the ground first? VSV 2015

28. As air pressure decreases, the potential for air resistance also decresases. VSV 2015

29. WHAT’S ORBITING?  AN OBJECT IS ORBITING WHEN IT IS TRAVELING AROUND ANOTHER OBJECT INTHE SPACE Orbiting and free falling VSV 2015

30. Launching a satellite The cannon ball must move very quickly to orbit the earth. The Moon orbits the Earth VSV 2015

32. THIS MOTION IS A CURVED PATH WHEN IT IS THROWN OR PROPELLED NEAR THE SURFACE OF THE EARTH MOTION PARALLEL TO THE GROUND MOTION DOWNWARD VSV 2015

33. READING: Gravity and Motion(590 – 597) Answer the 10 questions from page 597 in your notebook HOMEWORK VSV 2015