Solve Collisions Problem: Homework on Mass & Velocities

[Oatmeal11]

Homework Statement

An unstable nucleus of mass 1.70 10^-26 kg, initially at rest at the origin of a coordinate system, disintegrates into three particles. One particle, having a mass of m1 = 5.40 10^-27 kg moves in the positive y-direction with speed v1 = 7.20 106 m/s. Another particle, of mass m2 = 8.40 10^-27 kg moves in the positive x-direction with speed v2 = 4.40 106 m/s. Find the velocity of the third particle. (Assume that mass is conserved in this process. Indicate the direction with the sign of your answer.)

Homework Equations

m1v1i+m2v2i=m1v1f+m2v2f

The Attempt at a Solution

I found the mass of the third particle 1.7x10^-27-(5.4x10^-27+8.4x10^-27)=3.2x10^-27
I split it into X and Y components, and starting with the y i plugged into the equjation: 1.7X10^-26(0)=5.4x10^-27(7.2x10^6) + 0 + 3.2x10^-27v2f
V2f=-1.215x10^-7
I would repeat the same process for the x direction, but i tried entering this response into the y answer spot and it was incorrect. Please help me see what I did wrong and how to figure it out!

 

[Doc Al]

I found the mass of the third particle 1.7x10^-27-(5.4x10^-27+8.4x10^-27)=3.2x10^-27
I split it into X and Y components, and starting with the y i plugged into the equjation: 1.7X10^-26(0)=5.4x10^-27(7.2x10^6) + 0 + 3.2x10^-27v2f
V2f=-1.215x10^-7

Your method is fine, just redo the calculation. Mind your exponents.