#### Answer

$$F = 8.0 \times 10^{-8} N $$

#### Work Step by Step

$$F= G \frac{m_{1} m_{2}}{d^{2}} = (6.67 \times 10^{-11} \frac {N \cdot m^{2}}{kg^{2}}) \frac{(3.0 kg )(100 kg)}{(0.5 m)^{2}}$$
$$F = 8.0 \times 10^{-8} N $$
Comparing this to the answer in the previous question, we see that the obstetrician exerts roughly twice as much gravitational force on the baby as Mars does. The influence of Mars on the baby's birth is much smaller than the effect of nearby people.