00:01
So we have that an object explodes into three pieces, and we have a mass m going in the positive x direction.
00:12
So we've got m, and this is going in the positive x direction with a speed v equals 31 .4 meters per second.
00:22
And then we have another mass, which is also m, going at a speed v equals 31 .4 meters per second, in the positive y direction.
00:34
So this is going to be x and this can be y.
00:38
And then we have a third piece, and this has mass 2m, i should say.
00:44
But this third piece has mass 3m, and it's going to be, we want to work out what direction and velocity this will be going at.
00:53
So let's say it's going at an angle theta with respect to the horizontal, and it's going at a speed u.
01:03
Then first of all, so let's consider horizontal momentum.
01:08
Now since the thing was at rest before it exploded, the total horizontal momentum, p horizontal, is it going to be equal to zero.
01:19
And this is mv minus u cos theta times 3m, which means that we have the equation ucos theta equals v over 3.
01:40
So this is equation 1.
01:45
Now let's think about the vertical velocity which is also equal to 0, but this is 2mv minus 3m u sine theta...