Welcome to Day 30. September 29, 2009 Objectives SWBAT Recognize projectile motion SWBAT Solve projectile motion problems for objects Catalyst 1. Which will hit the ground first, a cannon ball dropped from a cannon, or shot from the same cannon? 2. A pelican flying along a horizontal path drops a fish from a height of 5.4 m while traveling 5.0 m/s. How far does the fish travel horizontally before it hits the water below? - 5.0m

Agenda  Catalyst (15min)  Review HW (10min)  Projectile motion for objects launched at an angle (15min)  Practice! (35min)

HW Answers  1..66m/s  m/s  m/s  m

Projectile Motion All projectiles follow parabolic paths.

Projectile Motion When a projectile is launched at an angle to the horizontal, it will have both an initial vertical component as well as a horizontal component. vivi V i,x V i,y HOW DO WE FIND THE X AND Y COMPONENTS OF THE V i ??

OUR KINEMATIC EQUATIONS!!!  v f = v i + a∆t  v f 2 = v i 2 + 2a∆x  ∆x = ½(v f + v i )∆t  ∆x = v i t +½a∆t 2  But we need them to be in terms of X and Y again… vivi V i,x V i,y Θ

Horizontal velocity…  Stays constant, phew.  V x =  ∆x = v i ∆t vivi V i,x V i,y Θ

Vertical velocity initial: v f = v i + a∆t  Get this in terms of y… vivi V i,x V i,y Θ

Vertical velocity initial: v f 2 = v i 2 + 2a∆x  Get this in terms of y… vivi V i,x V i,y Θ

Vertical velocity initial: ∆x = v i t +½a∆t 2  Get this in terms of y… vivi V i,x V i,y Θ

v x = v i (cosθ) = constant x = v i (cosθ)(t) v yf = v i (sinθ) + a(t) v yf 2 = v i 2 (sinθ) 2 + 2(g)(y) y = v i (sinθ)(t) + ½(g)(t) 2 Angular Projectile Motion

 A rock is thrown at 13 m/s and flies for 4s, if it hits the ground 30m away, what angle was it thrown at? 54.8 degrees

 The narrowest strait on earth is Seil Sound in Scotland, which lies between the mainland and the island of Seil. The strait is only about 6.0m wide. Suppose an athlete wanting to jump “over the sea” leaps at an angle of 35° with respect to the horizontal. What is the minimum initial speed that would allow the athlete to clear the gap? 7.9 m/s

 A zookeeper finds an escaped monkey hanging from a light pole. Aiming her trnquilizer gun at the monkey, the zookeeper kneels 10.0m from the ligh pole which is 5.00m high. The tip of her gun id 1.00 m above the ground. The monkey tries to trick the zookeeper by dropping a banana, then continues to hold onto the lightpole. At the moment the monkey releases the banana, the zookeeper shoots. If the tranquilizer dart travels at 50.0m/s, will the dart hit the monkey, the banana, or neither one? The banana.

A plane flies horizontally at 50.0 m/s. If the plane is 54.0 m above the ground, how far will the package travel horizontally before it hits the ground? 166 m

A cat chases a mouse across a 1.0 m high table. The mouse steps out of the way, and the cat slides off the table at a speed of 5.0 m/s. Where does the cat strike the floor? 2.3 m from the table

A pelican flying along a horizontal path drops a fish from a height of 5.4 m while traveling 5.0 m/s. How far does the fish travel horizontally before it hits the water below? 5.0 m

Practice  Pg 102, 1-4