1. An object that the only force acting on it is gravity Mr. P

2. Gravity accelerates all objects down regardless if they are going up, going down, stopped, or going sideways. An object that the only force acting on it is gravity is in Free Fall.

3. An object is in free fall if the only force acting on it is gravity, doesn’t happen though, near surface of earth there is air resistance!

4. An airplane can simulate free fall by flying in a parabolic path

5. All freely falling objects accelerate at 9.81 m/s 2 near the surface of the earth All are pulled down at the same rate regardless of their mass and direction of motion. ( Ignoring air resistance )

6. Without air resistance With air resistance Which falls faster without air resistance?

7. http://faculty.rmwc.edu/tmichalik/movies/tree.mpeg Galileo dropped a cannonball and a musket ball simultaneously from a tower, and observed that they both hit the ground at the same time. This contradicted Aristotle's long- accepted idea that heavier objects fell faster.

8. To solve free fall problems use the kinematic equations and: 1.a = -9.8 m/s 2 2.Dropped let v i =0 3.At top let v f =0

10. All of the following are in free fall, on the way down, up, or sideways

11. Note the lengths of the velocity and acceleration vectors at different times. (The upward and downward paths of the ball are horizontally Displaced for illustration purposes.)

12. Velocity vs. Time For an object thrown straight up at 20 m/s Acceleration vs. Time -9.81 m/s 2 20 m/s -20 m/s -30 m/s link

14. The slope of a velocity vs time graph for an object in free fall near the surface of the earth will always be -9.81 m/s 2.

16. EXAMPLE: An apple falls from rest from a tree and takes 1.5 seconds to reach the floor: a)How high up did it fall from? b)What is its velocity just before it hits the ground? a = - 9.81 m/s 2

17. A flea can jump to a vertical height of 4cm, find : a.The initial velocity the pest leaves the ground b.The time the flea takes to reach its maximum height

18. "A ball is thrown straight upward from the top of a cliff with an initial velocity of 15 m/sec. Assuming the ball just misses the edge of the cliff on its way down, how fast is it going just before it hits the ground which is 35 m below the ball's starting point?" 35 m