Another darned Physics (or Psycho) question. Any help greatly received.
Hi
The first question can be answered using... the conservation of the linear momentum of the two particles : we know their mass and their velocity, we also know that the mass of the coalesced particle is $\displaystyle m_A+m_B=4m$ hence
$\displaystyle \vec{p}_{\text{before}}=\vec{p}_{\text{after}} \Longleftrightarrow\vec{p_A}+\vec{p_B}=\vec{p_C} \Longleftrightarrow m\begin{pmatrix} 2\\3\end{pmatrix}+3m\begin{pmatrix} 6\\-5\end{pmatrix}=4m\begin{pmatrix} v_x\\v_y\end{pmatrix} $
And this can be solved for $\displaystyle v_x$ and $\displaystyle v_y$.
For the second question you've to compute the kinetic energy of the three particles since you're asked to evaluate $\displaystyle E_{\text{after}}-E_{\text{before}}=E_{c,C}-E_{c,A}+E_{c,B}$.
This question links nicely with this htread: http://www.mathhelpforum.com/math-he...ors-t-0-a.html