00:01
Hi, for this problem, i have a billard ball moving at 2 .2 meters per second.
00:11
It strikes another stationary ball.
00:14
Now, after they collide, we are told that one of the balls moves at 1 .1 meters per second under this angle that its velocity makes is 60 degrees.
00:31
And for the other ball, we don't know how it moves, but let's assume for now that it moves in this direction.
00:37
Let's call that v and let's call this theta.
00:43
Now we want to find the velocity of this other ball and we also want to check if this collision is inelastic or if it's elastic.
00:55
So remember, we use the conservation of linear momentum.
01:09
And so because we have this motion in two dimensions in x and y, i will start with an x momentum conservation.
01:23
And so you see that before collision, i had m into m multiplying 2 .2 for the momentum there.
01:36
And after collision, i have the same m multiplying 1 .1 in the horizontal direction.
01:45
This will be cost 60.
01:49
Plus the masses are identical and we don't know what this one is but it also has a v cost theta horizontal value i can cancel m on both sides and you can see that 2 .2 is equal to 1 .1 times 1 over 2 that is what consists is plus v cost theta therefore v cost theta will simply be 2 .2 minus 0 .5 and that will be 1 .65.
02:25
Let us skip that.
02:28
We come to the y momentum.
02:35
There was no y component of velocity before collision...