8-43 Two balls
of equal mass m undergo a collision. One ball is initially stationary.
After the collision, the velocities of the balls make angles of
31.1°
and 48.9° relative to the original direction of motion of the
moving
ball.
(a) Draw a diagram
showing the initial and final situations. If you are uncertain about
the
final directions of motion, remember that momentum is conserved.
(b) If the initial speed of the moving ball is 2.25 m/s, what are the speeds of the balls after the collision?
(c) Is this collision elastic? Justify your answer.
[Ans. (b) 1.18 m/s
at 48.9°; 1.72 m/s at 31.1° (c) no]
Correct!
In fact either (A)
or (B) is satisfactory. We will use (A)
What are the "before"
and "after" momentum components in the x-direction?
|
-
|
before
|
after
|
|
0
|
0
|
|
|
2.25m
|
(v1'
sin 48.9 + v2' sin 31.1)m
|
|
|
2.25m
|
(v1'
sin 48.9 - v2' sin 31.1)m
|
|
|
2.25m
|
(v1'
cos 48.9 + v2' cos 31.1)m
|
|
|
2.25m
|
(v1'
cos 48.9 - v2' cos 31.1)m
|