The function of ball bearings in a wheel is – (1) to increase friction (2) to convert kinetic friction into rolling friction (3) to convert static friction into kinetic friction (4) just for convenience
(2) to convert kinetic friction into rolling friction Explanation: A ball bearing is a type of rollingelement bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.