Answer
$14m$
Work Step by Step
In the given scenario
$p_a+p_s=0$
$\implies m_av_a+m_sv_s=0$
This can be rearranged as:
$v_a=-\frac{m_sv_s}{m_a}$
We know that
$d=v_{a}t$
$\implies d=(-\frac{m_sv_s}{m_a})t$
We plug in the known values to obtain:
$d=-[\frac{(-1200)(-0.14)}{92}](7.5)$
$d=14m$
