Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.

##
Physics 211, Quiz 10A

**
Question 1:
**

Two billiard balls have the same mass.
The 2-ball is at rest, and the 8-ball moves horizontally
towards it at 3 m/s.

8 ---> 2

After the balls collide, which of the following results
is impossible? Explain.
Case A: 8 2 --->
Case B: 2 -->
8
\
\
/
/
2
Case C:
8
\
\

Answer: The key is to ask if total momentum is conserved in
each case. The original total momentum is entirely
directed to the right -- that means that the final
total momentum must be completely directed to the right.
In case A, final momentum is directed to the right. Possible.
In case B, some of the final momentum is directed up. Impossible.
In case C, the final momentum may still be directed to
the right, if the vertical momentum of the
8-ball cancels that of the 2-ball. Possible.

Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.