Answer
We see that the gravitational force is .0812 percent as great as the force of the impact.
Work Step by Step
We first find the force due to the impulse:
$F=\frac{J}{s}=\frac{1.8\times10^5}{.12}=1,500,000N$
We now find the force of gravity:
$F_g=8.7 \times 140 = 1218N$
Comparing these gives the percentage, p:
$ p = \frac{1218}{1,500,000}\times 100= \fbox{.0812 percent}$
