center of mass

[Twigs]

Although this seems simple, I don't think I'm reading the problem right. Currently we are studying center of mass such as the velocity and position of the center of mass. The problem is a shell is fired from a gun with a muzzle velocity of 1500ft/s at an angle of 60 degrees with the horizontal. At the top of the trajectory, the shell explodes into two fragments of equal mass. One fragment, whose speed is immediately after the explosion is zero, falls vertically. How far from the gun does the other fragment land, assuming level terrain.

Im having trouble understanding how center of mass can be used in the problem. Any help getting me started with the problem is greatly appreciated.

[vsage]

The center of mass travels along the path that the shell would have taken had it held together (in a perfect world). Given the path that one fragment takes, you can find the trajectory of the other fragment. These two fragments must sum to the trajectory of the original shell (center of mass of the system). I hope this helps.