Can someone help me figure out what I am doing wrong? I am trying to determine the magnitude of the momentum before a co

[answerhappygod]

Can someone help me figure out what I am doing wrong?
I am trying to determine the magnitude of the momentum before acollision, and I am following the formula m1 * vf1 + m2 * vf2 = m1* vi1 + 0
My values are:
m1 = 0.116 kg vi1 = 0.446 m/s vf1 = -0.186 m/s m2 = 0.208kg v2i = 0 m/s v2f = 0.3525 m/s
Before you answer:
I tried working it out multiple times/ways and continue to getthe result 0.05174 kg * m/s, but it says that isincorrect.
The next question was "What is the mass of the 2nd cart (m2)?",which I successfully determined to be 0.208 kg, and it says that iscorrect. All of my values are correct, but I cannot figure out theinitial momentum!
Thank you!