#### Answer

The average collision force exerted on the object was 800 N in the negative direction.

#### Work Step by Step

We can use the information in the bar chart to find the impulse $J$.
$p_0 + J = p_f$
$J = p_f - p_0$
$J = -2~kg~m/s-6~kg~m/s$
$J = -8~kg~m/s$
We then use the impulse to find the average force.
$F~t = J$
$F = \frac{J}{t}$
$F = \frac{-8~kg~m/s}{10\times 10^{-3}~s}$
$F = -800~N$
The average collision force exerted on the object was 800 N in the negative direction.