1. Projectile Motion I 9/30/13

2. Bellwork What is free fall? The motion of an object under the influence of the gravitational force only (no air resistance)

3. Announcements Grades are up to date except for the Linear Motion Tests Any absent work needs to be made up by Friday 10/4/13 for the progress report Before school 7:00-8:00 am; Conference periods; also today and Thursday after school

4. Throwing a ball in the air On the way up: At the top of the throw: On the way down: velocity decreases acceleration stays the same. velocity zero acceleration stays the same. velocity increases acceleration stays the same.

5. Throwing a ball in the air The velocity changes. The acceleration is constant, it stays the same 9.81 m/s/s, downward throughout the flight.

6. Projectiles Projectiles: are objects where gravity and air resistance are the only forces acting Projectiles travel with a parabolic trajectory (path)

7. Lunar Lander Example http://phet.colorado.edu/sims/lunar- lander/lunar-lander_en.htmlhttp://phet.colorado.edu/sims/lunar- lander/lunar-lander_en.html

8. Projectiles A projectile’s horizontal component is independent of the vertical component The force of gravity does not affect the horizontal component of motion (i.e.) What is happening left and right does not effect what is happening up and down

9. Air Resistance Air Resistance: A force of friction that acts on an object moving through the air For projectile motion we will often neglect or assume that air resistance is extremely small

10. Projectile Terms Range: The distance a projectile travels horizontally from the initial position. Max Height: The greatest distance a projectile travels vertically Hang Time: The total amount of time a projectile is in the air

11. Mythbusters Dropped vs. Fired Bullet http://dsc.discovery.com/videos/mythbuste rs-dropped-vs-fired-bullet.htmlhttp://dsc.discovery.com/videos/mythbuste rs-dropped-vs-fired-bullet.html http://www.youtube.com/watch?v=D9wQVI EdKh8http://www.youtube.com/watch?v=D9wQVI EdKh8