1. Projectile Motion

2. Projectile Motion Motion in 2-Dimensions
Any object which the only force is gravity
Three types of Projectiles:
1. Dropped thrown vertically thrown at angle

3. Trajectory => Parabolic Path!!!

4. The trajectory of a projectile (due to gravity)
Projectile motion is a combination of HORIZONTAL and VERTICAL motions.
Horizontal motion is independent of its vertical motion
Projectiles have symmetric paths.

5. Lets look at the 2 motions of a Projectile separtaely
Horizontal
Vertical
NO horizontal forces acting
Force of Gravity
NO horizontal acceleration
Vertical acceleration due to gravity
Horizontal velocity is constant
-(9.8 m/s2)
Horizontal motion is independent of its vertical motion

6. Projectile Motion Webhunt3.

7. Newton’s First Law of Motion
An object at rest tends to stay at rest
and
an object in motion tends to stay in constant motion
(with the same speed and in the same direction)
UNLESS acted upon by an unbalanced force.

8. Newton’s 1st Law: An object in motion remains in motion...
Inertia cart demo

9. Inertia An object in motion (the moon)
will continue in motion at a constant speed
Orbiting the earth

10. 1. Where will the cannonball land when it is shot out of the truck that is moving at a constant velocity?
An object in motion (the truck AND the ball)
will continue in motion with the SAME constant velocity…

11. Projectile
Horizontal & vertical direction are INDEPENDENT of one another.
DOES NOT

12. Projectile Horizontal Vertical
Horizontal motion is independent of its vertical motion
Q: What is present to speed up or slow down the object?
Q: What is present to speed up or slow down the object?
Nothing pushing or pulling it
Gravity pulling downward
No horizontal acceleration
Vertical acceleration due to gravity
Horizontal velocity is constant
(9.8 m/s2)
Range:
d = v * t
“How Far”
d = ½ g t2

13. 0m m m 15m 20m 25m 30m m 40m 45m 50m 55m m 65m
I I I I I I I I I I I I I I
Cliff
0m __
5m __
10m __
15m __
20m __
25m __
30m __
35m __
40m __
45m __
50m __
55m __
60m __
65m __
70m __
75m __
80m __
85m __
90m __
95m __
100m _

14. If the car drove off the cliff with a velocity of 12 m/s, fill in the table below for the horizontal motion of the car at each time.

15. Fill in the table below for the vertical motion of the car

16. Projectile Motion Webhunt

17. Projectile
COMBINE the horizontal travel and the vertical travel (due to gravity) and the result is a parabolic path
Horizontal motion is independent of its vertical motion

18. Compare the horizontal TIME and the vertical free-fall TIME
1 s
2 s
3 s
4 s
5 s
1 s
1 s
2 s
2 s
In 1 sec. the ball moves horizontally AND falls vertically
at the same time.
3 s
3 s
4 s
4 s

19. Projectile
BOTH objects will fall at the same rate (acceleration of gravity 9.8m/s2)
The velocity it has in the horizontal motion does not affect or change or depend on the velocity and acceleration in the vertical direction.

20. Demo: Ball Dropped vs. Ball Fired
Mythbusters: bullet dropped vs bullet fired. (3 min)

21. Plane and the Package
Where does the package land relative to the plane??
When did it drop the package
Describe the HORIZONTAL VELOCITY of the package

22. Projectile Horizontal Vertical t = d v The TIME is the SAME! t
How Long time it traveled:
How Long of time of free-fall :
t = d v t

23. (time from maximum height to ground)
Projectile Motion
horizontal motion is INDEPENDENT of vertical motion
Horizontal motion is independent of its vertical motion
Horizontal
Vertical
How Far (“Range”):
How Far (high):
d = v * t
h = ½ g t2
How Long:
t = d v
t = √((2*h)/g)
How Fast:
Vfy = g*t
v = d t
(time from maximum height to ground) V

24. Step 2: Add “g= 9.8 m/s2” to the vertical given.
Step 1: Put the two “givens” in the proper place (horizontal or vertical)
Step 2: Add “g= 9.8 m/s2” to the vertical given.
Step 3: Solve for TIME! (using either horizontal or vertical, which ever one has two given)
Step 4: Use the time to solve for the other unknown.
Horizontal
Given
Unknown
Equation
Solve
Solution
Vertical
Unkown

25. If a cannonball is fired off a cliff at a horizontal
velocity of 100 m/s and hits the ground
85 m away from the cliff…
Predict:
1. The TIME required for the cannonball to hit the ground.
2. The vertical velocity of the cannon ball when it hits the ground.
Gx (Horizontal) U E S
Gy (Vertical)

26. A team of IPC students are in a plane 200 m above
the ground and traveling at 30 m/s. They needed
to hit a target on the ground with a water balloon
in order to earn an A+…
Predict:
1. The time required for the water balloon to hit the ground.
2. How far away should they drop their water balloon in order to hit the target? Gx U E S Gy

27. A bullet traveling horizontally at 800 m/s hits a target 180 m away
A bullet traveling horizontally at 800 m/s hits a target 180 m away. How far does the bullet fall before hitting the target? Predict: 1. The time required for the bullet to hit the target. 2. How far does the bullet fall before hitting the target? Gx U E S Gy

28. Projectile Simulator (if time)
Path of a projectile with and without air resistance

29. Projectile Angle vs. Range
Which cannon angle will launch the cannonball the FARTHEST range?

30. The 45° angle launched the ball the farthest
The 45° angle launched the ball the farthest. How does the range distance of the 30° and 60° angle compare?

31. Projectile Motion at an Angle
What is the SUM of the angles that land at the SAME distance (range)?
75° + 15° = 90°
60° + 30° = 90°