1. Objectives: The student will be able to:
Describe what is meant by a projectile.
Use the kinematics equations of Chapter Two along with the vector component method of Chapter Three to solve problems involving two dimensional motion of projectiles.
Analyze the motion of a projectile by breaking its velocity and acceleration vectors into vertical and horizontal components.

2. What is a projectile ?
A projectile is an object that has only one force acting on it. The singular force acting on the object must be gravity

3. What are they? The definition of a projectile is…
An object that moves through space affected only by gravity.

4. Projectile Motion and the NFL
Introduction to Projectile Motion

5. Projectile Motion Two-dimensional motion of an object Vertical
Horizontal

6. 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

7. Projectile or not? An Airplane A bird
A football thrown by Carson Palmer
A “dumb” bomb
A “smart” bomb
A bird that has just died in mid flight
A skydiver

8. Demonstration
Two identical metal balls are launched simultaneously. One is projected horizontally; the other falls only vertically. Which ball will strike the ground first?

10. Slow Motion Camera Two balls that start to fall at the same time.
The one on the right has an initial speed in the x-direction.
It can be seen that vertical positions of the two balls are identical at identical times…
while the horizontal position of the yellow ball increases linearly.

11. Projectile Motion Horizontally Acceleration is zero! Vertically
Acceleration is due to gravity
Time of flight is equal for horizontal and vertical movement.

12. Observe independent vectors

14. 3-5 Projectile Motion
A projectile is an object moving in two dimensions under the influence of Earth's gravity; its path is a parabola.

15. Demonstration
When the plunger in the dynamics car is released, the ball is launched straight up. Will the ball land in front of, in, or behind the moving dynamics cart?

18. 3-5 Projectile Motion
It can be understood by analyzing the horizontal and vertical motions separately.

20. 3-5 Projectile Motion
If an object is launched at an initial angle of θ0 with the horizontal, the analysis is similar except that the initial velocity has a vertical component.

21. Draw velocity vectors for this. Label the magnitudes

23. 3-6 Solving Problems Involving Projectile Motion
Projectile motion is motion with constant acceleration in two dimensions, where the acceleration is g and is down.

25. 3-6 Solving Problems Involving Projectile Motion
Read the problem carefully, and choose the object(s) you are going to analyze.
Draw a diagram.
Choose an origin and a coordinate system.
Decide on the time interval; this is the same in both directions, and includes only the time the object is moving with constant acceleration g.
Examine the x and y motions separately.

26. 3-6 Solving Problems Involving Projectile Motion
6. List known and unknown quantities. Remember that vx never changes, and that vy = 0 at the highest point.
7. Plan how you will proceed. Use the appropriate equations; you may have to combine some of them.

32. At the 2003 World Punkin’ Chunkin’ Championships the winning chunk was launched with an initial speed of 113 meters/sec. At an angle of 45 degrees
Determine: 1. The horizontal and vertical components of velocity 2. The time of flight for the pumpkin (wow) 3. The range of the pumpkin

33. 3-7 Projectile Motion Is Parabolic
In order to demonstrate that projectile motion is parabolic, we need to write y as a function of x. When we do, we find that it has the form:
This is indeed the equation for a parabola.

34. p. 66 #17
A tiger leaps horizontally from a 6.5 m high rock with a speed of 3.5 m/s. How far from the base of the rock will she land?

35. Sample on page

36. Homework Chapter 3 Question: page 65 #15 Problems: 18, 19, 21, 22
Extra Practice
Projectile Motion – Guided activity

37. Closure Kahoot (Projectile Motion)
How does the downward components of the motion of a projectile compare with the motion of freefall?

38. Homework Chapter 3
Problems: 26, 31, 35