Which of the following types of motion are oscillatory? i.a diving board when used by a diver. ii. the motion of the balance wheel of a wrist watch. iii. the motion of the turn-table of a record player. iv. the motion of the center of a ten kobo piece as it rolls down an inclined plane. v. the motion of the needle of a D.C. ammeter into which a low A.C. current is passed