Answer
(a) the same as
(b) more than
(c) $0.70m/s^2$
Work Step by Step
(a) We know that according to Newton's third law, the force experienced by the parent on the child and the force experienced by the child on the parent are the same in magnitude as they place their hands together and push.
(b) We know that
$F_p=F_c$
$Ma_p=ma_c$
The mass of the parent $M$ is greater than the mass of the child $n$. Therefore $a_c\gt a_p$ -- that is, the acceleration of the child should be greater than that of the parent.
(c) We know that
$a_p=\frac{ma_c}{M}$
We plug in the known values to obtain:
$a_p=\frac{(19Kg)(2.6m/s^2)}{71Kg}$
$a_p=0.70m/s^2$
