00:02
This is a conservation of momentum problem.
00:04
You're told two billiard balls that are identical.
00:07
So the mass of each is going to be equal.
00:10
Collide in a perfectly elastic collision.
00:13
So both momentum and kinetic energy will be conserved.
00:16
You're told that v1i, the initial velocity for object 1, is 2 .2i.
00:22
This is in unit vector form, minus 0 .4j.
00:27
And v2i, the second sphere, its velocity is 1 .4 .4.
00:32
Negative 1 .4i and 2 .4j.
00:41
And you're told that when they collide, sphere 1 is at the origin.
00:45
So this is the x -axis and the y -axis.
00:49
Sphere number one is right on the origin...