1. Horizontal Projectiles Physics Mrs. Coyle

2. Horizontal Projectiles are launched with a horizontal initial velocity.

3. Horizontal Projectiles http://www.physicsclassroom.com/mmedia/vectors/hlp.cfm

4. Remember “Boat and River”

5. Motion in Two Dimensions http://www.physicsclassroom.com/mmedia/vectors/hlp.cfm

6. Which falls first? A free falling object Or A horizontal projectile from the same height

7. Which falls first? A horizontal projectile Or A horizontal projectile from the same height with a higher initial horizontal speed

8. Question A zoologist is aiming at a monkey with a tranquilizer gun. Both are at the same level. The monkey is about to jump. Should the zoologist aim horizontally or low in order to tranquilize the monkey?

9. Horizontal Projectiles Two dimensional motion Initial velocity is entirely horizontal X-axis : constant velocity Y-axis : constant acceleration

10. A Look at the Velocities V x = constant V yi =0 V y = a t

11. Animation http://www.physicsclassroom.com/mme dia/qt/vectors/hlpwin.cfm http://www.physicsclassroom.com/mme dia/qt/vectors/hlpwin.cfm

12. Characteristics of Path Trajectory Parabola Range

13. Equations for Horizontal Projectiles x direction: use any equation for const. velocity motion y direction: use any equation for const acceleration x=v x t ____ y= 1 at 2  t= √ 2y/a 2 v Y =at

14. Example 1 A cannon ball is fired horizontally from the top of a 90 m tall cliff with an initial velocity of 20 m/s. a) How long did the ball take to reach the ground? b) What was the range? c) What was the x and y-velocity of the ball right before it hit the ground? Answer: a)4.3sec, b) 85.7m c) V x = 20m/s V y =42m/s

15. Example 2 A diver dives horizontally out from a 9 m platform with a velocity of 3m/s. How far out did he dive (range)? Answer: t=1.35s, x= 4m

16. http://www.walter-fendt.de/ph11e/projectile.htm Projectile Applet