physics
posted by shaz b .
David and his father sat at the end of a seesaw 2 m from the pivot. where should David's mother sit in order to balance the seesaw

Hard to say with that little information about masses.

Force multiply by distance(1)+ force multiply by distance(2)= force multiply by distance(3)
400N multiply by 2m + 600d =700N multiply by 2m
800+600d=1400
600d=1400800
600d=600
d=1m 
400N multiply by 2m + 600d =700N multiply by 2m
800+600d=1400
600d=1400800
600d=600
d=1m