Question

A 4.0 kg ball is moving at 4m/s to the right and a 6.0 kg ball is moving at 3.0 m/s to the left. The total momentum of the system is,

Answer 1

\[\huge \vec{\text{p}}=m\vec{\text{v}}\]Since velocity is a vector, then that means we also have to account for direction. Luckily, we're only considering two dimensions here, so the problem is quite simple.
The total momentum of the system will be:\[\huge \sum \vec{\text{p}}=\sum_i^n (m_i\vec{\text{v}}_i)\]
Splitting this up, we have
\[\huge \vec{\text{p}} = m_1\vec{\text{v}}_1+m_2 \vec{\text{v}}_2\]
Do you know where to go from here? Just plug in everything you are given! (**Including direction!**)