A 68 kg adult sits at one end of a 10.5 m long board. His 35 kg child sits on the other end.
(a) Where should the pivot be placed so that the board is balanced, ignoring the board's mass?
______m (measured from the adult)
(b) Find the pivot point if the board is uniform and has a mass of 15 kg.
______ m (measured from the adult)