Copy down December calendar In your next available page in your notebook.

Notes: Projectile Motion projectile- any object launched, thrown or shot through the air under the force of gravity. (neglecting air resistance) http://phet.colorado.edu/new/simulations/sims.php?sim=Projectile_Motion trajectory – path followed by projectile shape is a parabola parabolic curve- where every point is the same distance from the focus as it is from the directrix.

Types of Projectile Motion Horizontal Motion of a ball rolling freely along a level surface Horizontal velocity is ALWAYS constant Vertical Motion of a freely falling object Force due to gravity Vertical component of velocity changes with time Parabolic Path traced by an object accelerating only in the vertical direction while moving at constant horizontal velocity

Discuss with your group wither these are projectiles or not and why? Is a frisbee a projectile? An airplane? A rocket?

Parabola http://www.richland.edu/james/lecture/m116/conics/paradef.html

Lable Vy (red) and Vx(blue) are they constant,(-) or (+)

Range – max Dx traveled by projectile Height – Dy at given time Max height of projectile, Vy = 0

Label range, heights, and max height on sheet of paper

X-motion and Y-motion are independent Trajectory of object can be resolved into components to find two independent velocities Ax = Acosq = Vx Ay = Asinq = Vy ***Strategy – both horizontal motion and vertical motion are connected by the variable time (Dt) at the same point on a trajectory. Solving forD t in one dimension gives Dt in the other dimension.

Horizontal Projectile

Equations X- Component Y- Component Vectors Note: g= 9.8 m/s^2

Class Exercise A ball is projected horizontally from the edge of a table that is 0.862m high, and it strikes the floor at a point 1.42m from the base of the table. It takes three seconds to reach the floor. The acceleration of gravity is 9.8m/s2. Find yf

Explanation: Choosing the edge of the table as the origin of our coordinate system, we have y= viy(t) - 1/2g(t)2 With viy = 0 so that y=-1/2g(t)2

foldable Inside in the middle write: g= 9.8 m/s2 g will always be vertical acceleration Horizontal acceleration will always be 0 Write variables for x,y,Vi,Vf,Vix,Viy,Vfx,Vfy,Xi,Yi,Yf,t

outside

Inside

Class Exercise Cont’d A toy car runs off the edge of a table that is 1.066 m high. The car lands 0.5632 m from the base of the table. How long does it take for the car to fall? The acceleration due to gravity is 9.8 m/s2. What is the horizontal velocity of the car?

Summary Projectiles travel with a parabolic trajectory due to the influence of gravity, There are no horizontal forces acting upon projectiles and thus no horizontal acceleration, The horizontal velocity of a projectile is constant (a never changing value), There is a vertical acceleration caused by gravity; its value is 9.8 m/s/s, down, The vertical projectile is any object upon which the only force is gravity, Vertical velocity of a projectile changes by 9.8 m/s each second, The horizontal motion of a projectile is independent of its vertical motion.