Answer
Before the impulse, the speed of the particle was 80 m/s in the negative direction.
Work Step by Step
We can use the information in the bar chart to find the initial momentum $p_0$.
$p_0 + J = p_f$
$p_0 = p_f - J$
$p_0 = 2~kg~m/s - 6~kg~m/s$
$p_0 = -4~kg~m/s$
We then find the initial velocity $v_0$ of the particle;
$m~v_0 = p_0$
$v_0 = \frac{p_0}{m}$
$v_0 = \frac{-4~kg~m/s}{0.050~kg}$
$v_0 = -80~m/s$
Before the impulse, the speed of the particle was 80 m/s in the negative direction.
