1. Two Dimensional Collisions
Unit A Momentum

2. POS Checklist
explain, quantitatively, that momentum is conserved in one and two dimensional interactions in an isolated system

3. Diploma Question:

4. Diploma Question:

5. Diploma Question

6. Just as momentum is conserved in 1 dimensional collisions,

7. In situations where objects are moving in two dimensions (i. e
In situations where objects are moving in two dimensions (i.e. the x and y direction), we need to break the momentum vectors into components.
The components in the x direction will be conserved and the components in the y direction will be conserved.

8. Collision Simulator

9. 2-D Collisions and Conservation of Momentum25 65 B1
vA = 4.20 m/s
vA’=3.80 m/s
vB’=1.80 m/s A1

10. Danger: Momentum is always conserved (in isolated system).
Velocity is NOT conserved.
Ek may or may not be conserved.
Always find answer based on initial or final momentum, not velocity or Ek.

11. Right Angles
ex) A 4.0 kg cat is traveling South at 2.8 m/s when it collides with a 6.0 kg bat traveling East at 3.0 m/s. The objects stick together upon collision. What is the velocity of the catbat system?

12. Step 2: Write separate conservation statements for x and y directions.
x direction y direction
Step 3: Find final momentum in x and y direction

13. Example 2: A 1. 06 t Mazda going at 46. 0 km/h E collides with a 1
Example 2: A 1.06 t Mazda going at 46.0 km/h E collides with a 1.85 t Chrysler going 29.0 km/h N at an icy intersection. Right after the collision, what is the velocity of the entangled wreckage? E N
Chrysler
Mazda E N
Draw diagram.
Calculate momenta. *

14. *

15. Diploma Question

16. Two-Dimensional Collisions
Example 1: Compute the southern and western momenta of a 74.6 kg cyclist travelling at 6.35 m/s  39.0 W of S.
39 N E W S N E W S
1. Calculate momentum *

17. Assignment:
Workbook p. 58 #1 - 3