1. Bellwork What are projectiles? *** Turn in “Projectile Lab” ***
They are objects where gravity and air resistance are the only forces acting

2. Projectile Motion II
10/2/13

3. Components
Component: the projection of a vector quantity along a perpendicular axis

4. Components
Horizontal
Right = +x
Left = -x
Vertical
Up = +y
Down = -y

5. Projectile Quantities
Displacement (m)
dx = horizontal displacement
dy = vertical displacement
Velocity (m/s)
vx = horizontal velocity
vy = vertical velocity

6. Projectile Quantities
Acceleration
ax = 0 m/s2 (no horizontal acceleration)
ay = m/s2 or “g”
Time (s)
t = time
- Does not depend on direction (scalar)
- It is the same for horizontal and vertical components

7. Projectiles and Time
(i.e.) A projectile has the same time for how long it goes up and/or down AND left or right

8. different distances each second. Yes, constant 9.81 m/s/s, downward
Quantity
Horizontal
Component
Vertical Component
Displacement
Yes,
same distance
each second
different distances each second.
Velocity
Constant
Yes, changing
by m/s each second.
Acceleration No
Yes, constant 9.81 m/s/s, downward
“g”

9. Notes End Here

10. Projectile Example
What happens to a projectile’s horizontal and vertical displacement, velocity and acceleration?
Example: An object with a initial horizontal velocity of 20 m/s to the right and vertical velocity of 0 m/s.

11. Displacement Time Horizontal Displacement Vertical 0 s 0 m, right 0 m
5 m, down
2 s
40 m, right
20 m, down
3 s
60 m, right
45 m, down
4 s
80 m, right
80 m, down
5 s
100 m, right
125 m, down

12. Velocity Time Horizontal Velocity Vertical 0 s 20 m/s, right 0 m/s 1 s
10 m/s, down
2 s
20 m/s, down
3 s
30 m/s, down
4 s
40 m/s, down
5 s
50 m/s, down

13. Acceleration Time Horizontal Acceleration Vertical 0 s 0 m/s/s
10 m/s/s, down
1 s
2 s
3 s
4 s
5 s

14. A falling object

15. A falling object

16. Projectile (Horizonal)

17. Projectile (Launched)

18. Next Lab You will be able to calculate the horizontal velocity
From this you will make a calculated prediction where it will land on the floor

19. Formula Cards Component axis Horizontal vs. Launched
Projectile y-component
Projectile x-component