Answer
The baby applies twice as much pressure to the floor, which is a difference of $52,000~N/m^2$
Work Step by Step
We can find the average pressure exerted on the floor by the baby's stool:
$P = \frac{F}{A}$
$P = \frac{mg}{3\pi~r^2}$
$P = \frac{(10~kg)(9.80~m/s^2)}{(3)(\pi)(0.010~m)^2}$
$P = 104,000~N/m^2$
We can find the average pressure exerted on the floor by the adult's chair:
$P = \frac{F}{A}$
$P = \frac{mg}{4\pi~r^2}$
$P = \frac{(60~kg)(9.80~m/s^2)}{(4)(\pi)(0.030~m)^2}$
$P = 52,000~N/m^2$
The baby applies twice as much pressure to the floor, which is a difference of $52,000~N/m^2$
