Can I get some help on these questions?

A mass m1 moves along the x axis with velocity of magnitude v0 on a frictionless table. It strikes another mass m2 which is initially at rest. The mass m1 goes off along the y axis. If half the original kinetic energy is lost in the collision, with what speed and at what angle does m2 leave the point of collision?

A block of mass 50kg is sliding along a frictionless table with a velocity of magnitude 4 m/s. (Call this +x direction.) It splits into three pieces after an internal explosion - one with mass 15kg goes off in the +x direction with velocity of magnitude 6 m/s. A second piece, mass 10kg, goes off perpendicular to the original direction, but still in the plane of the table, with velocity of magnitude 3 m/s. (call this the +y direction.) Find the velocity of the third piece. How much energy was given off in the explosion?

http://answers.yahoo.com/question/index?qid=20091114134505AAcGm7M

Both of these are conservation of linear momentum problems. pi=pf. Remember momentum is a vector so the conservation of momentum must be done in both the x and y directions.

Thanks Threadsticker, but the link is also my exact same question but on Yahoo! Answers. Also, I have tried everything, I just can't seem to get the right answer...

panic.

lol... it's so stupid.