A stationary boulder explodes into four pieces. After the explosion, three of the pieces have masses and velocities as follows:
M1: 2.5kg, V: 9.0 m/s due east
M2: 3.5kg, V: 27 m/s due west
M3: 2.0kg, V: 15 m/s due north
M4: 3.8kg, V: ?
The Attempt at a Solution
therefore m1v1+m2v2+m3v3+m4v4 = 0
Here is where I get confused: does the momentum for Mass 1 and 2 "cancel out" since they're in opposite directions? I tried plugging everything in as positive numbers and solving for v4, but that's obviously wrong ):
Thanks for your time and patience!