Horizontal Projectiles Physics Mrs Coyle Horizontal Projectiles are

Horizontal Projectiles Physics Mrs. Coyle

Horizontal Projectiles are launched with a horizontal initial velocity.

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

Remember “Boat and River”

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

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

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

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?

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

A Look at the Velocities Vx= constant Vyi=0 Vy = a t

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

Characteristics of Path n Trajectory n Parabola n Range

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

Example 1 a) b) c) A cannon ball is fired horizontally from the top of a 90 m tall cliff with an initial velocity of 20 m/s. How long did the ball take to reach the ground? What was the range? What was the x and y-velocity of the ball right before it hit the ground? Answer: a)4. 3 sec , b) 85. 7 m c) Vx= 20 m/s Vy=42 m/s

Example 2 A diver dives horizontally out from a 9 m platform with a velocity of 3 m/s. How far out did he dive (range)? Answer: t=1. 35 s, x= 4 m

Projectile Applet http: //www. walter-fendt. de/ph 11 e/projectile. htm