What is the Final Momentum of Three Colliding Balls?

[ScullyX51]

Homework Statement

A red ball is heading due east, a blue ball is moving due west, and a green ball is moving north. They have initial speeds vr,i=20 cm/s, vb,i=10 cm/s, vg,i=10 cm/s. The red ball has a mass of 5 g, the blue ball has a mass of 10g, and the green ball has a mass of 5g. The three balls all collide, and stick together. Find the magnitude and direction of the final momentum of the composite.

Homework Equations

the sum of P_I=the sum of P_F

The Attempt at a Solution

Ok...without plugging the numbers in this is what I have so far:
I don't really know how to approach this problem, so if someone could tell me if I am starting it on the right path would be great.
I broke it up into x and y components, and for the x component of momentum I have:
M_BV_B-M_RV_R=(M_R+M_B+M_G)V_FX)

Then for the y component I have:
M_GV_G=(M_R+M_B+M_G)V_FY)

Am I on the right track...or completely missing the point?

 

[tiny-tim]

Hi ScullyX51!

Ok...without plugging the numbers in this is what I have so far:
I don't really know how to approach this problem, so if someone could tell me if I am starting it on the right path would be great.
I broke it up into x and y components, and for the x component of momentum I have:
M_BV_B-M_RV_R=(M_R+M_B+M_G)V_FX)

Then for the y component I have:
M_GV_G=(M_R+M_B+M_G)V_FY)

Am I on the right track...or completely missing the point?

Yes, that is exactly the right track …

momentum is a vector, and so it obeys the laws of vector addition …

sometimes physics is that easy!