What is the Velocity of the Third Object After Explosion?

[VanKwisH]

Homework Statement

An object explodes into 3 equal masses. One mass moves east at a velocity of
15.0 m/s . If a second mass moves at a velocity of 10.0 m/s 45degrees south of east.
What is the velocity of the 3rd object

Homework Equations

I know m1 = m2 = m3 therefore we have just M

The Attempt at a Solution

I have no idea where to start ... can anyone help me get started at least??

 

[Feldoh]

Momentum has to be conserved from the Center of mass but you were never given an initial velocity I don't think you can solve it?

EDIT: Did the object explode form rest?

 

[VanKwisH]

yes it exploded from rest, and my teacher said in this case there is no friction ...

 

[Feldoh]

yes it exploded from rest, and my teacher said in this case there is no friction ...

Momentum has to be conserved for the center of mass of the individual particles, which equaled 0 before the explosion, can you see where to go form here?