 Now once again we do a quick check of units, we've got mass divided by mass so that gives us nothing and we've got velocity equals velocity so that works well and it's fairly obviously the same on the bottom line. Let's also check limits. There are lots of limits we can pick so to start with let's assume that the first mass isn't moving which means the second mass just goes straight up into it and then we'd expect them to go straight up. So if we look down at our equations down here if the first mass wasn't moving that would be zero so this would be zero and so this thing here would not be moving sideways which is correct and it would be moving straight up instead. However if this mass say was zero we'd expect no matter how fast it was going it wouldn't really change the trajectory of the first particle. So if we go down here and set mass two to zero then what we get is that this is zero because the top line there is zero and so we'd find that it would be going only in the horizontal direction and indeed it'd be going the same velocity it always was. So in other words if this had zero mass even when they stuck together the velocity of the first mass would be unchanged like a tiny insect running into a truck and that's exactly what our equations say is the limits look good and if we wanted to work out the angle at which these two masses move after they stick together then we can easily work that out in terms of the components because what we have up here is the y component of velocity and the x component of the velocity and so the tan of theta is going to be the ratio of those two which is just going to be and so you can see that the tan of that angle is just going to be the ratio of the momenta of the two particles.