I know if taking the integral of $F=ma$, then I can get $p=mv$. I'm weak in calculus, so I wondered how to do this exactly.
Is there anything wrong in my logic below?
\begin{align}\int F\left(t\right)\,{\rm d}t&=\int ma\,{\rm d}t \\ &=m\int a\left(t\right)\,{\rm d}t \end{align} where by definition, $\int F\,{\rm d}t=p$ and $\int a\,{\rm d}t=v$. Plug these in above, I get, $$p=mv$$
Equivalently, how to derive from $m_1a_1=m_1a_1$ to $m_2v_2=m_2v_2$?
Can I do
Since $$a_1=\frac{{\rm d}v_1}{{\rm d}t_1},\quad a_2=\frac{{\rm d}v_2}{{\rm d}t_2}\tag{1}$$ and $$m_1a_1=m_2a_2\tag{2}$$ Plug (1) into (2), then get $$ m_1\frac{{\rm d}v_1}{{\rm d}t_1}=m_2\frac{{\rm d}v_2}{{\rm d}t_2}\tag{3} $$ where ${\rm d}t_1={\rm d}t_2$. Then plug this into (3) to get, $$m_1{\rm d}v_1=m_2{\rm d}v_2$$ With $v_1={\rm d}v_1$ and $v_2={\rm d}v_2$, therefore $$m_1v_1=m_2v_2$$