1. Aim: How can we define 2D projectile motion?
Do Now: Quiz
HW: Problem Set

2. Projectile Motion
Acceleration = -9.8 (m/s)/s Motion is in the X & Y Direction! How is this different form an object moving in only 1-D?

3. White Board Activity
With your group sketch and label all points of interest for a marble rolled horizontally off a desk.
Make a kinematics chart.

4. As the red ball rolls off the edge, a green
ball is dropped from rest from the same
height at the same time
Which one will hit the ground first?
They will hit
at the SAME
TIME!!!

5. DEMO: Horizontal Ball Drop

6. Example 1
A ball is rolled off a table with an initial horizontal velocity of 5 m/s from a height of 1m. What is the distance the ball travelled horizontally?
What do we know?
Y-axis
ViY = 0
aY = -9.8 m/s2
dY = 1m
t = ?
X-axis
ViX = 5 m/s
aX = 0
dX = ?
t = ?

7. Horizontal Projectile: FACTS
All kinematics equations apply, but only in a SPECIFIC direction (x or y)
Time horizontally (x) = Time vertically (y)
Recognize the velocity VECTOR is tangent the projectiles path and has components.
Viy = 0, ay = -9.8 (m/s)/s
Make 2 charts… One for each direction!

8. Example 2
Firing a gun Horizontally I’m skeet shooting on top of a cliff that is 75 meters high and I fire my gun horizontally with an initial velocity of 31.3 m/s. How long was the bullet in the air if I miss and how far away does it land?
Bring in an actual nerf gun and figure out in class the initial velocity

9. Angular projectiles
Using the white boards, sketch the path of a kicked soccer ball. Label all points of interest and variables.
Sketch a diagram on the board

10. Projectile Diagram

11. Describe a step by step procedure for solving a projectile motion problem.
It should work for horizontal or angular!

12. Solid Procedure A) Sketch a picture with labels.
B) Draw a small chart separating the vertical and horizontal components.
C) Identify the initial horizontal velocity.
D) Determine the initial vertical velocity.
E) How can we calculate the time it takes the object to land? (hint: think of the demonstration)
F) Where does the object land?