Answer
a). If the masses of the children are different the seesaw can never balance because the net torque about the axis of rotation will not be zero.
b). Net torque = 0
So, $w_{1} .2-w_{2}. d=0$
$35g \times 2 - 30gd=0$
$d=2.33m$
Work Step by Step
a). If the masses of the children are different the seesaw can never balance because the net torque about the axis of rotation will not be zero.
b). Net torque = 0
So, $w_{1} .2-w_{2}. d=0$
$35g \times 2 - 30gd=0$
$d=2.33m$